One more step down the road to random testing in the UK, won't be long now.
My contract with the last Company I flew for specified we could be random checked and we were on occasion.
In fact they took hair samples to check for drugs as well as alcohol.
I believe many airlines have similar contracts these days so nothing new about random checks.
In circa 40 years of airline operation I have never flew with any crew member who was anywhere near intoxicated - all the colleagues I came across were well aware of the responsibility to be fit to operate.
Fatigue is a far bigger issue.