Don't play RTG. I play microgaming, netent and a few more. Around 100 casinos. None of them have any max cashout rules. So for me the standard in casinos is no max cashout. He even asked with the specific bonus code and got the answer no max cashout. It can not be any clearer than this. I don't care if he tried to take advantage of the casino or not. I do that all the time. Ask for bonuses, comps etc. Guess what, I have always been paid or had what any live chat support person have told me. Anything else would be a scam IMHO. Of course obvious errors can't be honored, but max cashout or no max cashout is a pretty clear question impossible to missunderstand.
FYI, I have never heard or seen a RTG ND deposit without a max cashout, the terms differ from casino to casino, but all the RTG's have max cashouts. I take my position of them not having to honor because I am used to this standard with RTG. I have even tried to put myself in the OP's position. Now I wouldnt ask what the max cashout is because the terms are normally written with the codes, but I am pretending that I did ask and they said no max cashout on a code. I pretend I get it to $5000.00. I go to cashout and they say the max is $1,000.00 because it is 10x max and my ND deposit was $100. I would be upset, I would take it up with someone, but after I was told that there was nothing they could do because it was standard, I would then have to get over the frustration real quick and be happy I won something on a free deposit.