Acts 19:38

“If therefore Demetrius, and the craftsmen who are with him, have a matter against any man, the courts are open, and there are proconsuls. Let them accuse one another.”

If Demetrius and his craftsmen really did have a criminal charge against these men, or against anyone, then the periodic courts were available, and they could bring the matter before the proconsuls. Let them accuse one another there, and not in this unofficial way, which could only cause trouble.

The plural for proconsuls may simply be a general reference, indicating the generality of proconsuls, as there would normally be only one in the region. On the other hand it is an interesting historical fact that around this time there was a short period when there were seemingly two proconsuls in this region.