And the club advice will change from:
If you do the wrong thing and use a match day banned drug during the week, tell the club doctor and find out if you've still got it in your system.
to
If you do the wrong thing and use a match day banned drug during the week, tell an external GP and find out if you've still got it in your system. Here's a list of places that you can get a test done quickly.
What's the difference? The club doctor is their GP. It just means they'll be encouraged to go to a different place to get tested - with no connection to the club.
It's just like encouraging a kid to have an STI check if they have unprotected sex - it isn't encouraging or enabling - it's minimising harm when they make choices that you don't want them to make.
Can’t imagine too many regular GPs with a non sporting background willing to make a forecast of whether the drugs will still be in the system in two days time.