Quite frankly, Freebitco.in are laid back when it comes to this kind of security and VPN issues. I myself, have not received any issue accessing my account with different VPN. Also, way back when I'm only earning crypto on different faucet sites, freebitco.in was also one of my go-to platforms and honestly, I had multi account on these faucet sites and I also haven't received any issue with withdrawing my faucet earning on this platform (I stopped doing faucet a long time ago). I'm not quite sure if things have change with that but it's better to be cautious than be banned on the platform.
I have the same experience, way back when faucet are very popular, I also have multiple account on this site because my pc crashed and I am unable to recover my accounts. When I got my new unit, i reregister in freebitcoin and I also use VPN every now and then and yet I have had no issue using the site ever since.
We may have attested that VPN isn't an issue as a way of accessing the account but I believe it is best to ask their customer support to make sure that it is really not a problem. @OP it is your money, so better do extra precautions by inquiring about things you wanted to know to the representative or the cs of Freebitco.in