Explanation:
The security guard(s) don't have to approach/question/order-to-leave EVERYONE, only people who are apparently breaking the rules, appearing suspicious etc.
E.g. Security may have thought the women worked at the bank, or worked nearby (which they did, apparently), and the women may have been quiet/nice and NOT suspicious/annoying etc.
Security DON'T have to throw out everyone, who is breaking the slightest rule or being slightly suspicious, etc.
They decide who they are going to go for, and then politely ask them to leave, if necessary.
Without seeing the location in question, and how it is reached, from the public side of things, it is VERY difficult to conclude how "Public" or "Private" it was in practice.
i.e. There is a picture earlier in this thread, but I would need to see the surrounding areas and stuff, to get a feel for if it seems private or public.
Speculation: It looks private to me, because of all the neat tables and seating.