It's a college thing when going to class. When I went back to school 94-98 ( I was 26), it was easy to dress like that especially when you are too tired to figure out your wardrobe after a night of studying (or going out)!
I usually had a ball cap with my ponytail stick out, flannel pants or shorts, t-shirt and a hoodie sweat shirt.
The other style was wearing leggings with a really baggy sweatshirt or huge flannel shirt over it.
Today I wouldn't wear PJ's in public. What is interesting I am seeing high school kids running around like that. Nothing ever stays in college.
So it is funny that you posted this because I had just posted something similar myself no to long ago. Being honest I have done this....Plaid bottoms with a band tee or a tank and oftentimes a hoodie. It really all comes down to comfort and where your comfort zone is. I have no problem being the mom that every one loves to stare at. I have often left the house with a pencil holding my hair in place wildly painted fingernails kool aid dyed hair and pj's. My kids love it and they really get a kick out of the whole "look what I did to mom today" look.
I have gone to the grocery store, the record store,bookstore, and other various places as such however I would never go to work like that. I wouldn't be able to feel professional enough.
Java