Sometimes when I tried to use Tor for privacy to sign up, I would get a message along the lines of You cannot register at this time. If this error persists contact us. Given that this error can sometimes be circumvented by resetting identity in Tor, I suspect this may be some form of IP address-based ban, as presumably, many spammers and trollers also use Tor to abuse the site.
Is this really just an unexpected error or is it possible for an IP address to become banned from registering accounts? If so, why present this in the form of an Error instead of a You cannot register at this time due to the volume of accounts being registered to post spam and abuse from your network type message?