Out of curiosity, were these people warned in some way previously, or do we no longer give out warnings?
If someone is overbumping, they are typically warned. If they are making an effort to delete their posts and rebump as a workaround an established rule, that means they obviously know about the bumping rule and are knowingly breaking it. Warnings are set in place for those who don't know the rules, need a reminder, etc, not as a cushion for those who think they will be safe breaking the rules expecting a warning shot before the hammer.
Deleting old bumps (should be) a rule on pretty much every marketplace like forum, plus deleting old bumps keeps the seller's thread "clean" and easy to read.
The 24 hour limit on bump frequency is an arbitrary time (which I agree is a fair amount of time), which may be different in other marketplace forums. Some forums may limit bumps to every 24 hours, others may limit bumps to every 72 hours and others may limit bumps to every 6 hours. I don't think it is fair to say that someone knows that bumps should be limited to once every 24 hours just because they remove old bumps.
Out of curiosity, were these people warned in some way previously, or do we no longer give out warnings?
I give out warnings if they're reported as bump spamming but if they ignore it they get a ban. It's getting annoying though and difficult to enforce effectively. Far too many scammers just coming back on alt accounts and spam bumping day after day. I seemingly spend half of my time here removing bumps and nuking banned digital good spammer scammers.
Also some moderators will post asking users to delete old bumps after they delete old bumps, this serves both as a warning to the specific user, and allows this rule to be more visible.
