Can anyone confirm if a purge can target people offline?
according to the devs, yes (usually about 18:00 - 22:00 in local time in official servers)
but you can manipulate it in private server
From what I understand, if you are in a clan, all that is needed is for 1 member to be on to get hit. Now there are settings that a server admin can change that will change when purges can happen, how strong the are, and how often they hit.
There is a Setting that says, paraphrased, “Minimum number of people online for Purge”.
Its default is Zero.