I have a wonderful ring sling that is a mesh type material for the pool. No one has ever said boo to me about wearing it (got tons of compliments though) and it's nice to wear out of the pool because it's light and cool for both me and my son.
I've worn a mesh ring sling to a CHicago pool - Whealan pool on Devon. No problems. THe only thing that freaked me out was not having the ability to really go after my older kids if they were in danger. I guess that's why the lifeguards are there.