Touts (generally African immigrants) aggressively try to encourage you to come grab a drink with them, trying to be all friendly and acting shocked that you might not want to come with them when they want to shout you a drink in a bar. Once in the bar (who's in on it), the scam ranges from charging you way too much to buy ladies drinks, through to drugging and robbing you before dropping you home.
They'll never get physical with you beyond getting really close in your personal space and trying to shake your hand, but if you don't acknowledge them and walk past them then they often don't even do that. Their target is young white male tourists with lots of cash who wanna get drunk and party with ladies.
