This seems a reasonable idea - but I suspect it would have little effect in practice.
We already know that the people who flood the foum with these threads read absolutely nothing that is placed before them & apparently get no news about anything from anywhere other than their personal tiny screen.
I think a "gate form" would just add one extra click to the inevitable entry of yet another "my phone does not work when will it be back on will I get compenation" thread.
Still - it has to be worth a try. The other alternative when nothing is working would be to shut the H&S forum down with just a large font banner page announcement in it's place - this would not actually reduce the effectiveness ot the forum as it is already totally unusable at these times.