I think a lot of things use pre-shrunk fabric these days. I've got t-shirts that haven't shrunk, and t-shirts that have. Unfortunately a lot of band shirts bought at concerts fall into the latter :(.
Note that I fully understand it for the anecdotal weight that it has. That is, basically none. Is fun for conversation, but isn't intended to prove anything.
At this point I thought you were going for an ahem heavy-handed joke.
Might have been our new hangers.
On that last, I almost forgot I had direct evidence. We visited a place that shrank some of our clothes that we had washed many times back home.
dryer settings,
local environment in the laundry room.
Probably in that order.