You are right. In fact I think that men who date men might be more vulnerable, since sometimes they don't get the warnings. And I've seen older men trying to get younger men drunk. Sometimes gay, sometimes heterosexual.

For what I've seen, some men confuse the advances as "just being friendly", not being hit on. In my country people drink as a way to socialize, so it is not extrange that someone that you just meet is only being friendly. I mean, sometimes gay men have invited me because they enjoyed dancing with me (I'm a woman, so they wasn't interested) and I've seen gay men invite other men without being interested in sex. So for men it might be more confusing to discern between an honest invitation, someone flirting (also honest but with intention) or someone trying to get advantage of you. In case that you are curios about what we were doing there, we were "wingmen and wing women" for our gay friend. Sometimes people don't like to go alone to discos and is more fun as a group. Also safer.