I'm not sure about this, but I have my theory, it is not a secret that as long as we have different IP address, GO won't consider them as multi id, probability they were created by lots of people to help their own towns, especially for fort battle purpose where numbers are something. If we find out a town with lots of new face with those low levels, then we can be assure that is their multi id.
Also don't forget about all those spamming messages are always coming from a level 1 fresh guy.