I think there are two kinds of travelers in the world for the most part. There are people that are overly nervous about everything and over-prepare for any imaginable situation, and then there are people like me. The people like me are the ones that have been traveling for so long that they probably don't take the various processes very seriously and this can result in you having a bunch of anxiety when the systems change and nobody tells you about it.
I recently discovered this on a trip to Mexico, which I consider to be a home base of sorts and they changed a great deal about their immigration policy without alerting us.... and honestly, why would they tell us about that? It's our job to be informed, not the other way around.
This self-service kiosk for immigration was something that I truly wasn't expecting to encounter in Mexico. No offense to Mexico or Mexicans, but that isn't the part of the world that I normally associate with being high tech. When you consider that it was just a little over a year ago that I arrived in Mexico and this same airport in Guadalajara looked like a 1970's bus station with water dripping out of the ceiling and members of what I can only presume are the military that were wandering around the airport with rifles shouting things at people in Spanish.
The stamp I received on that trip was smudged and the person behind the glass didn't really seem all that concerned about where I was coming from or where I was going. This is one thing I have appreciated about Mexico in the past. I have no idea what their official stance is on travel or tourism, but they seemed very laid back about the entire thing.
However, on my last trip into Guadalajara, I never spoke to an actual human the entire time I was going through the immigration portion of the airport and it was extremely modern by international standards.
This isn't a bad thing at all because it was moving a lot faster than it would have been if the military were shouting at all of us in a language that I barely speak and then you got a rubber stamp from a person that as far as I could tell didn't even look at me.
The issue that you face is when I was departing from that same airport, there didn't seem to be any immigration at all. There was no sectioned off area that you expect to see in airports all around the world where everyone lines up like cattle and gets their passport evaluated by someone who has been programmed to show no emotion whatsoever.
I was a bit concerned when I got on my plane that I had somehow managed to bypass Immigration and was going to be in trouble for having done so. It was a very long time ago, but I somehow managed to leave Singapore without going through Immigration and was now at the Malaysia border and they kept asking "where is your exit stamp?" and while I was completely innocent in this situation because I honestly didn't see the customs area on the Singapore side of things... the officials were not wrong and they made me go back and get a stamp.
So even though I am American and was flying from Mexico to USA, I was concerned because of all the immigration posts in the world I think the ones in USA are the most serious.
As it turns out Mexico has gone mostly "stamp-free" now and there are many countries in the world that are like this now. If you think about it, this makes a lot more sense than something like a rubber stamp that could be counterfeited rather easily.
There are other changes that you need to be aware of as well and many of these things are happening in countries all around the world with something I don't understand why it exists at all. They are called arrival cards and you have likely seen them before.
i've always found these things to be rather pointless because you could really just write down whatever you wanted to and even in today's information age they wouldn't be able to determine if you are telling the truth or not. It got to the point where most of the officials that I encountered that were collecting these things didn't even look at them because for them (I presume) this was just one more piece of BS that they had to deal with in their jobs each day.
Most countries have eliminated these outright as they convert to digital or just scrap the process altogether. However, there are some countries that are holding out on this process and their reasons are their own and they don't have to tell us about this either. Recently a friend of mine was traveling to Indonesia and was unaware that they had transitioned to a digital arrival card system that must be completed within 72 hours prior to arrival. He didn't know this and somehow was allowed onto the plane anyway. When he arrived in Indonesia, the officials were very upset with him for having not completed the online form and treated him very badly for not knowing about it. In the end the put him on the wifi and let him fill it out.
But here is the thing: How was he supposed to know this? Perhaps it was pointed out to him in the fine print of the airline ticket but as someone who regularly travels I can totally understand why he wouldn't have read that. I never read past the part of the printout - that I do not print - beyond the flight details.
I do not know of any country that will actually deny you entry because of not doing this, but I think I speak for most people when I say that I would rather not chance it. It has been my experience with nearly 30 years of travel under my belt that the people who work in Customs and Immigration of countries tend to be least willing to help you type of people in any profession in the world. They have the ability to be mean to you with impunity and it is better to just be aware of this. That is not the right place to go "Karen" on someone since they can basically do whatever they want to you.
A good website where you can get an overview of requirements for entry based on your own nationality is Passport Index and it is free. This is not the end-all though and honestly, if you are going to a country for the first time I think it is best for you to thoroughly search, perhaps at that nations own website, to get the most up-to-date information.
Like I said: I recently found out first-hand how these things can just change without notice like it did to me in Mexico.
Airports are stressful enough without unknowns like this, so be prepared!