Yes, 90% of cafes would, because just like Omegle, it's not their job or ability to monitor every single interaction between every single person and identify whether a conversation is appropriate.
Crimes happen on all technologies and in all venues, and they likely always will.
By their own case the explicit activity didn't even take place on omegle. The perv met the kid and went elsewhere. Of course that wouldn't be prevented in a cafe.
Crimes happen on all technologies and in all venues, and they likely always will.