While they're at it, IF they were serious, they could also stop common scams, like 'taxi no meter', or 'I will now switch off meter and you pay me 500 baht for the 10 minutes into town' as soon as you step out of the airport... (Alternatively, allow Grab & Co. at the airport. 😉)
(And yes, I know, there is a taxi booking counter at Don Muang, but who wants to wait another two hours or so, after more than half a day on plane, in airports, and at Immigration...)