This is not a technology problem.
The sale of RC aircraft may need to further regulation. So far it's been mostly a self regulated process through the AMA helping RC pilots follow safety procedures and comply with FAA rules. But most hobby shops will sell you anything you want without checking for an AMA card, but some of them do at least mention it to those new to RC.
A callsign, license and test, like done in HAM radio, seems like the obvious solution to me. Hobbyists need to understand the rules and be liable when they break them.