Of having a has-been 90's child icon who's most likely piss poor as the banker. But anyway, it really wouldn't surprise me if the contestant was "in on it". It's all obviously a fix. No-one ever leaves with over £10,000. The phone always rings when Noel has said something "funny" or has stated the obvious, and then he makes an "Oh dear" face and waits for about 5 minutes before telling us what was offered. If there really was a banker he might just decide he didn't want to play any more and not bother to call back, and where would that leave Noel? Ever so slightly embarrased and maybe even tempted to do another "Noel's House Party".
In case you're wondering i did have a point to make but i've forgotten what it was...