I also believe that paying a little extra so that you could withdraw from casino is a very important thing. You could wait for it from some other person because you could chat with them and ask how it is going or check blockchain if it is gone and so forth, you could do that from an exchange because you can see it there and you know what is going on and it is riskless.
Sorry but I didn't understand what you mean.
But, when we are talking about a casino I feel like we should be very careful about it, like take your money out of a casino as soon as possible the moment the you want it and you should be getting in a minute or less. The reason for this is that the longer you linger the more you may end up spending, so pay a little more but get out right away.
The moment you asked for withdraw from casino, your funds are proceed and you aren't able to gamble, i.e. when you click the withdraw button, you are no longer to gamble, so, there is no problem in this case I guess and it has nothing to do with the time of transaction process and then confirmations on blockchain.
Btw there are some solutions for these kind of users even without withdrawing:
1. Ask to freeze their account for a while (you won't be able to unlock it even if you request).
2. Some casinos offer additional wallet where you can lock your funds.
Btw that's the personal problem that needs to be treated, it means that you are addicted to gambling and like other kind of addictions, this one can ruin your life.