Yes, weirdly enough. People make new accounts, create (or generate?) a bunch of crap PRs (e.g. adding random words to READMEs, shuffling whitespace around, ...) in repos they picked somehow, ... to get a free t-shirt in the end.
Initially, at least from what I remember, the "spam" mostly was purpose-made repos a la "make a PR in this repo to add your username to this list and get a Hacktoberfest point", which didn't drain others time. But now it spreads to random projects, since they try to block those purpose-made repos.
Haven't figured out yet which repos are picked why, it doesn't seem to be entirely random. Seen it on some projects I'm involved with, others not at all. As mentioned in the article, the HTML spec is hit every year. ...
Maybe they should either just give you a t-shirt on sign up or not give a t-shirt at all but prizes to the best contributions or something like that. I'm unconvinced that the prospect of getting a t-shirt would incentivize someone to put a lot of effort in a contribution. I feel like people who do put in the effort would do it regardless of the t-shirt.
