Doesn't usually work. There are over a thousand incursions by unmanned aircraft systems along the U.S.-Mexico border each month, per the NORAD commander: https://www.war.gov/News/News-Stories/Article/Article/370778... . They pretty much never result in shutting down air space or launching missiles.
Responding to a single party balloon with a giant laser, thus causing a saner government official to close the airspace because some moron is firing giant lasers into the air, is unusual. Probably not a usable asymmetric attack vector.
wow maybe we should stop giving the law enforcement orgs weapons of war
'saner govt official because moron firing giant lasers into the air' - lasers just go everywhere at once and hit everything in the air, into the stratosphere? it's a big sky and gets bigger the higher you go.