I am many many years out of practice.
There is a friendly attendant where I swim who makes a point of chatting. Nothing more, just friendly chit chat. I am not at my best and it's highly unlikely to be anything more than friendly.
But I found myself mulling over flirting. I assume there is always a risk of flirting with someone who is not single. Eek. Maybe if it's all fairly light and the person isn't interested then no harm done/no huge embarrassment?
It would be terrible to make someone feel awkward when they have been nice and are just doing their job.