If you curve the aluminium foil somehow, you can actually refelct it back. They did tests on youtube where they used a flipped riot shield and it work.
Sounds like you could make a curved protest sign with plywood and then hide some foil between the plywood and a paper/cardboard layer for a fairly inconspicuous shield that can block and even reflect both microwave and sound cannons.
If you curve the aluminium foil somehow, you can actually refelct it back. They did tests on youtube where they used a flipped riot shield and it work.
Sounds like you could make a curved protest sign with plywood and then hide some foil between the plywood and a paper/cardboard layer for a fairly inconspicuous shield that can block and even reflect both microwave and sound cannons.