It is a shame that bonuses are not really considered seriously by the sites, as if they were something optional or just a gesture of good-will. A bonus is an agreement for someone influencing their friends or other people and promoting you image. That is not free and it takes time so if the site then scams or re-thinks is reason enough to provide public feedback and negative trust.
Sorry bt, dis is only a part to it and I get it that, you aren't speaking of the overall bonus systems but, referrer bonus often works in times where you have the gamblers to have input his or her referrer codes. In most cases, these bonuses are given separately in a bonus column and gives you the leverage to play games rather than withdrawal or even topping uo to withdraw. All that just doesn't work with the system.
I think where th1 complains often comes is in terms of where these bonuses are not readily accessible to gamblers in the sense that, you really can't compete with the big stakers and your required to have gambled away a capped amount within a time frame to be eligible for the bonuses or even qualify for a raffle.