My son is on holiday here in Singapore having flown out of the UK via Heathrow airport on a SIA flight.
Heathrow has a security system which requires a closer search of every 100th passenger. Strangely it does not target any ethnic groups or pay any attention to passenger history or previous countries visited or body language etc. This would be too complicated and anyway is too politically correct for UK.

So my son was the 100th passenger and they gave him an "invasive" search in full view of other passengers. He idly enquired if they had "a room for this sort of thing" but they did not.
They found nothing. Not even the 6-inch Brigade blade he had carelessly overlooked in his bag!