All you'd need to do would be to make some of the messaging conditional. The page already restricts the dropdown to the older models when Gemini 4 is not accessible so all the information is already client side and they could grey out a box and display a message.

It is just sheer incompetence that this isn't near the top of their QA checklist.

Heck, even just a message saying it may not be available for all users yet would go a long way. Instead the way it currently works a lot of people will think they're testing Gemini 4 while they're in fact using Gemini 3.6 Flash and getting awful results.