The existing code,

auto to = to_acnts.find( value.symbol.name() );
if( to == to_acnts.end() ) {
    to_acnts.emplace( ram_payer, [&]( auto& a ){
    a.balance = value;
});
} else {
  to_acnts.modify( to, 0, [&]( auto& a ) {
    a.balance += value;
  });
}

This means that should the receiver not be pre-existing in the table with the corresponding symbol then the sender pays the RAM cost to create a record to do so.

What if we created a preexisting record where there was a 'register' method which allowed anyone to call it and create an empty record in the to_acnts table, with a balance of 0.0000.

Then, your own computer can listen for such action, check if they're on the airdrop list, and then trigger a transfer action, transferring the tokens to the receiver without such RAM cost.

This wouldn't cast the net as wide as one would like as not every planned recipient would hit this 'register' action, however, you could have an 'Airdrop period' where if you do his this action, you're guaranteed to get the token early/day 1, if you don't, then you'll have to wait a little longer.