I used to be a lot on r/travel. Back then there were posts with pictures that had upvote ls in the triple to quadruple digit range. There were also user questions, usually in the double digits.
Now the majority is just discussions that mysteriously have thousands of upvotes. And some of them quite boring. That must be bots or fakes directly by reddit. No way this happens naturally.
Is this common practice now or is that something r/travel did specifically?
For vote manipulation, no.
For faking user engagement and creating content and pretending like hordes of actual humans haven't left and real eyes are actually looking at all these ads, yes.