It's not that unusual. I think it's rare that someone would specifically wear 2 t-shirts, but it's extremely common for people to wear a t-shirt over a long-sleeved shirt, or for women to wear a long tank top underneath a shorter tank top (or variations on this theme) for a layering effect, at least in America.
If it's worth saying, but not worth its own post (even in Discussion), then it goes here.
Notes for future OT posters:
1. Please add the 'open_thread' tag.
2. Check if there is an active Open Thread before posting a new one. (Immediately before; refresh the list-of-threads page before posting.)
3. Open Threads should be posted in Discussion, and not Main.
4. Open Threads should start on Monday, and end on Sunday.