Huh, never considered the splint trick, works brilliantly as a cover story for having the stuff as well if you tuck the applicator in a medkit.
Of course, the weight issue is still a thing, after rechecking War!, barrier foam canisters are indeed handheld, and can create 10000000 cubic centimeters of barrier foam. to put that in perspective, a cubic centimeter of air weighs about 1.2 grams, 10 million times that is 12000 kilograms, so unless barrier foam weighs less than air, that handheld canister is impossible to lift.