What pains me the most is the clash of the VPN. To some users, they will not know, and instead for the casino to investigate if the clashing that causes the allegation of multiple accounts is a mere coincidence, they will just block the customer's account and that ends this. This is so unfair, and to avoid it from the beginning is a very good thing.
I mean if you don't check their ToS before you create an account and play their games, then the fault lies in you. Most casinos explain their terms properly, and you can search with keywords like "VPNs", "proxy", "unblocking tools", etc if you don't want to read the full ToS.
I think you are the one who did not get the gist correctly. This is not about the terms and conditions of casinos but how VPN usage could put gamblers in trouble. Some companies may not allow the use of VPN, while some will indeed allow it, it all depends, but what I buttressed upon is the situation where the casino allows the use of VPN and was clearly stated in their terms and conditions even as you contacted their support staff to confirm it to be true.
But still, this can put you in trouble if VPN's IPs clash, that's what I was trying to explain here. In so much as you are not assigned to a unique IP by the VPN provider, you can't be sure that someone elsewhere is not using the same IP you are using as well. Now, if the two of you or more are gambling in the same casino, especially the one that doesn't allow a user to have more than one account which is the common practice nowadays. What do you think the casinos will take the accounts for?
Of course, they will believe it is multiple accounts, which I believe must have violated their terms and conditions. In most cases, they will lock your account without further investigations, but the good ones with a conscience will investigate further to ascertain if indeed the accounts are being owned and operated by the same person. That's my plight in my last post.