The same thing happens with exchanges, yet somehow people keep singling out the swap services. There are countless nightmare stories for most exchanges on Reddit.
I'm sure the same thing has been said for exchanges. Most experienced members that I know of aren't fond of this kind of practice, whether it occurs on an exchange, instant swap service, casino, or elsewhere. Maybe you haven't seen their posts yet.
It's a shame that a lack of transparency has gradually become the norm nowadays. Not sure what are the reasons for that, hopefully it will get better in the future.