SourceSleuth doesn't detect VPNs but players that connect with the SAME IP as a currently banned player, which means:
- This player is ban evading (70%+ chance)
- This player is from the same family/house, but not the banned one (?% chance)
- The banned player was using a VPN, and this player has the same VPN as him, and is connected on the same server (unlikely, but can happen)
- The banned player had a dynamic IP, and this player now has the same IP as the banned one because he has a dynamic IP too (0,001% chance)
Note that if this player connects less than a day after the original ban, there's 99% chance he is ban evading. Check account age as well to try to avoid false positives.