Who defines what a "pro" is anyway? Someone who wins a lot? I guess the theory of the books is, "We want you to win, but not too much." Or conversely, "We want you to lose - a lot." It's a risky business for both parties - operator and bettor. If either one is not willing to take on the risk, then they shouldn't be involved in the business.
Regarding the bonuses, I could understand not allowing the bonus amount itself to be withdrawn (i.e., leaving at least that much in the account). But a bettor should be able to withdraw their deposit at any time; again, down to the amount of the bonus.
The only plus, even if you have to eventually forfeit the bonus, is that you can use it as leverage on your bets in the beginning. If I get a $500 bonus to start, then get say, two winners off of it for $1,000, then it's still worth it initially.
Regarding the bonuses, I could understand not allowing the bonus amount itself to be withdrawn (i.e., leaving at least that much in the account). But a bettor should be able to withdraw their deposit at any time; again, down to the amount of the bonus.
The only plus, even if you have to eventually forfeit the bonus, is that you can use it as leverage on your bets in the beginning. If I get a $500 bonus to start, then get say, two winners off of it for $1,000, then it's still worth it initially.