In the Bing implementation the slide is sealed by a very thin rubber diaphram and if it cracks the cylinder(s) being fed by that carb make(s) no power.
That is reportedly a not unknown failure on the Conti altitude compensated fuel servos.
The engine stops.
You need to be quick on the mixture lever and pull it right back.
And it still doesn't work properly, because while it is doing altitude compensation, one actually needs to be measuring
mass flow of the air, in order to maintain the correct stochiometric mixture.
Metering mass flow on the fuel is trivial because it is liquid, and any constant volume pumping device (e.g. a gear pump) will deliver a constant mass flow. But measuring mass flow on the air is a lot more complicated if you want to do it to the accuracy required to maintain stochiometric combustion from SFC to say FL120 or more.
One can use a simple altitude compensated carb to make the engine work ok to FL120 without any pilot adjustment, but it won't be running optimally.