As far as I can see, no one said that a pilot should be grounded on the say so of ATC. All they have called for is that when multiple people report the same pilot that the CAA should not just ignore the complaints; they should INVESTIGATE. They shouldn't just take back the pilot's licence; they should investigate the reports and make a decision on the basis of what they find.
I can't see them doing anything without sufficient evidence to be able to justify their actions in court. They are hardly THAT stupid, and have access to enough legal knowledge to know what they are doing.
Flying under the influence of any mood altering drugs, be that E, wine or other alcohol is stupid, dangerous and illegal, no matter what generation it is (as is trying to make your own fuel from paint tinner
)
dp