For the sake of spam, of course. It would be neat for the IPs of these accounts to be blacklisted in order for them to pay in creating accounts, but then again they could as easily be using VPNs.
by default all nuked/banned accounts will get their IPs (at posting time) blacklisted, evil units added
and yes, if smart they are most likely posting via VPNs... so they can register more accounts from clean IPs
A spammer testing his bot? And maybe testing the response time, all
30 involved accounts have been nuked.
probably as you said, testing/tuning his bot or someone misconfigured his bot settings
and he didn't even try to cover his acts, he's using an easily recognized pattern on all usernames