This is something that is sometimes and issue for us because when we go to find new trails in order to keep our runs fresh there is one thing that is always on our minds. We do not own the property that we are running on and many times we don't actually even know who the property belongs to.
We try to stay off of private land and we never go near any crops but for the most part we just wing it and hope that no one gets upset.
Sometimes, and I will admit this even though it is obviously there for a reason, we will even violate fences that have been erected to specifically keep people off their land. I'm a little worried whenever this happens because people don't generally put up fences if they don't mind people coming on their land. It hasn't happened very many times, but there have been instances where the owners would actually come to the places where we gather afterwards and confront us in an angry fashion for us being on their property.
I don't understand why they would get upset at times but then again, I think about how we treat private property in the west, particularly in America, and perhaps we should consider ourselves lucky that we have never been shot at or chased away by dogs.
Other areas, such as those that are around Temples are a bit safer because the temples tend to own a great deal of the land surrounding it and since we make rather large donations whenever we host runs there and are very respectful of all the religious relics, they monks or other people involved with the temples don't seem to mind.
Generally speaking, Thai people are pretty damn friendly and we also have a bunch of Thai people in our groups to help to smooth things over should anyone get upset with us. I try to look at it from their perspective. If I lived on some large plot of land outside of a city and all of a sudden 30 Asians were running through my land, I would be very alarmed. Thankfully, this process very rarely results in us getting into any trouble and the police have never been involved.
If people pursue us and come to our start / finish locations they find a bunch of people in silly outfits that are drinking beer and singing songs. We on many occasions have invited them to come and join us and at least one of these people that was originally angry with us ended up actually JOINING the Hash for future runs. Once people see that we mean no harm and are just a bunch of adults that don't want to grow up, mostly they are cool with it.
On the rare instance that someone wont let it go and insists on being a jerk about it, we tell them that we will never return to their property and apologize. They are correct after all, we are trespassing and this is still illegal. Thankfully, in the many years that I have been involved in this, it has never resulted in any sort of aggressive conflict.