There is one ad that I really think should be banned (and I am not a 'ban it' type at all), and that is the one with a wordsearch where the answer is stupidly easy, so vulnerable people will be sure to find it. The prize is about £15k, with extra if you can 'solve' another puzzle, and costs up to £12 to enter.
They make a big deal of how the phone call to enter only lasts a minute - harking back to the days when calls were charged by the minute, and the actual cost of the call is in the small print, which might not be easy to read for an elderly person.
The odds must be high, the prize is very low compared to the cost of entry, and IMO the whole thing is very exploitative.
Also, the entry is by telephone, so the organisers will have the number of the entrants, and I'd be surprised if they don't use it to contact them again. It is usually on during programmes such as Poirot, obviously in the hope of targeting an older market.