Many thanks for the warning.
We came across a team of pick pockets at the Sunday market in Los Cristianos many years ago. The police arrested them on the market but when we were waiting at the bus stop to travel back to Los Gigantes we found them in the queue. One of them who looked like thug stood to one side and we guessed that he was there to intervene if there was trouble. Our friend announced their presence to the queue and they all just walked away. We wondered why the police hadn't detained them.