> These are probes. Judging responses and response times.

Some, yes. Many are merely defective units. These weapons are being manufactured in enormous quantity and deployed rapidly with minimal quality control: based on the reported numbers over Ukraine, the net manufacturing rate is about 10 per hour. Inevitably, some are defective and fail to follow waypoints. Romania is on a line through numerous targets in Ukraine from the Kursk region where many Russian drone flights begin, so Romania ends up being the unintended destination.

The good news is that the defects likely represent resource problems for the manufacturers. The same phenomena has been noted with increasing failed missile launches from Russia.

Can you elaborate on the last sentence? It sounds crazy.

Occam's razor. Decoy drones with a bit more fuel or favorable wind.