Yes I have ever recommended Betcoin.ag to my friends, mostly when they complain if they're got scammed, they're not lucky or the odds is too low. If they didn't complain anything, I would recommend anything because it's not the right time to convince other people, they need to have a problem in order to use your solution.
I always remember this too and don't really want to recommend anything that concerns money, gambling or even investments, because in case of success or winning, the player will think that it is entirely his merit. At the same time, if he loses, he will completely think that it is our fault. This is how human psychology works and there is nothing surprising about it. Sometimes I even try to restrain myself, because I want to recommend many things to my friends in gambling, but then I imagine these situations in the future and my desire to recommend something quickly disappears.
I would simply don't care at all, if they think they can get rich through gambling, then they're stupid.
As long as they sign using my referral and I have warn them, I don't care about other thing. Problem is inevitable, but you can control how you react.