This VPN topic, have already been discussed even with the manager campaign from Duelbits.
They can accept VPN as long not for abusing platform, that's mean to avoided some restricted country example like in the slot from the provider it self. You can use VPN, but can't use them to break any kind activity against the platform like (Restricted country from casino, abused promotion, self referral, etc).
makes sense
but that brings a question
how would they know if you are using a VPN to bypass a restriction from determined country or not?
since your true location would be masked.