Two blimp tethers intersecting an infinity of D.C. target vectors is no more reasonable than the risks of air-shots so blandly accepted here. "Stupid is as stupid does."
It's more economic stimulation through FedGov regulation, expending the last of the stored helium to drive its costs up just like buying all the ammo. Or do you think the blimps will be filled with hydrogen? Are tracer rounds still legal or have they been made illegal too?