Are there techniques that don't involve high risk and/or couldn't be seen as structuring or money laundering?
A prosecutor representing the government will "see" the situation however best suits the government's agenda, so the short answer is no. I'm going to avoid giving advice for a couple of reasons: 1) doing so could be interpreted as racketeering in one of our present-day fantasy courts, and 2) you or I might use these techniques to enhance personal privacy, but there are others out there who really would launder the proceeds of violent crime or theft, and I don't think the government makes much of a distinction.
I hope math is enough to win the day. Maybe we can figure out how to use math to fight drones.

Math might not be enough to shoot a drone out of the sky, but we can certainly develop warning networks. There are more of us than there are of them.