You should not put loose items into the security trays. Everything needs to be bagged. My DH is such a fool - just empties his very large pockets with all sorts of shit swimming in the security trays - watch, passport, money, phone, tech etc all on display. I put a rucksack into the security tray with a jacket carabiner clipped to it. I sometimes have a bumbag as well which is also on the carabiner clip so that there is nothing to easily grab individually.
People book flights every single day purely to steal stuff in airports, not to actually go on holiday. They just fly back and do some more stealing. I know someone who had their family's passports in a little holder and they were stolen going through security. They literally had to cancel their holiday as they had no passports!