LogFAQs > #934725489

Depending on whether or not there's more to the story (doubt it, but maybe), yeah that sounds pretty bs.
If he has insurance (and can easily prove it, like you say) but doesn't have the paper in his car, you'd think the first instance would be a warning or at worst a ticket. Not getting fucking towed.

reason posted...

Keep your insurance card in your car. Simple as that. It's not the cop's responsibility to look up your documents. Just depends on the cop, though. Maybe he'd already done it a few times that day for other people and your buddy caught him at a bad time? Who knows?!

While it's possible that's why, it's not at all an excuse and one would hope the traffic court judge would throw this out once he goes there.