...//...:
Please, I don't understand your ideas or comments, but can you provide some additional information or an example of a last withdrawal, what is your last withdrawal fee charged and in which casino?
...//...: I can't see how it is intuitive enough to help sustain the site and may even cause problems with coding. Might as well just use a faster cash out option, lower the costs and advertise it to many people so you gain back the losses you got from lowering the transaction fees. ...//...

...//...: :...//....That should work as I've seen it from a couple of cryptocurrency sites already.
which sites?