Well, call the tights Lululemon and the answers are: of course and everywhere! Varying degrees of quality and thickness to tights/leggings.
I say whatever you are comfortable with.
Initially I want to say "Yes, that sounds sexy" but then I realize that there are so many people who I'd rather not see dressed that way.
Fine if the top covers ya arse and ******... I wear just leggins and a top a lot
Stuff em... if it looks good on you wear it!!!
I've gone out a few times wearing black leggings, a long sweater, and black ugg style boots just like the gals wear in the winter. Got a few snickers from the young gals (teenagers) otherwise not much if any reaction at all.
It's gotta depend on you. I mean if you are a ninety year old, wear a burka. If you are are reativly young, and in good shape, just wear a baggy t-shirt, no panties, and carry the leggings/tights in a bag. Every guy you pass on the way will probably offer to help you carry whatever it is your buying.
I've seen this on many occasions going to and from the gym. Ladies coming out and grabbing a coffee with their friends, running a few errands and just going about their daily routine all in leggings.
I have also see guys (fit and in shape) wearing compression or running tights too and stop in at the gas station to pick up some milk on the way home, or drop some mail at the post office.
It's become more standardized these days as leggings and tights are becoming a regular part of peoples wardrobes. It's not an issue with them.
I say go for it.