It is not really a "trap" perse, it is still a promotion and you could still get it. However it could have been worded much better I will agree with you guys on that. Normally if they worded this correctly, with "get upto 50 dollars on deposit bonus" that would be enough, you do not have to talk about the requirements because no other casino does that neither, its gamblers duty to check what the requirements are. After all have you seen any place that marketed it "get upto 50 bucks on your deposit with some requirements of rollovers before you can withdraw"? Nobody does that at all, it is just deposit bonus and everyone knows it.
However saying it is a sign up bonus is not really a great wording of it, definitely does hurt the image a bit but I am sure it wasn't intentional.
I would say having more like "$50 deposit bonus" could be enough, there is no need to overdo anything right now, deposit bonus and sign up bonus have different meanings to different people and I think this goes to deposit bonus side.
The difference is, when you say sign up bonus, people think only thing they have to do is sign up and that's it, they get free money no matter what, they still expect rollover or should expect it because nobody is going to give 50 bucks for free without any requirements, you would go bankrupt in an hour if that was the case, everyone would open up a million accounts to withdraw 50 bucks. So, sign up bonus is fine when you consider giving 50 bucks to test but have HUGE rollover requirements to be able to withdraw anything. But this requires deposit as well, hence why it should be deposit bonus and not sign up bonus.