Quite likely it is policy/SOP to restrain anyone transported. And imagine the blast of disrespect these officers got from a couple of pubescent brats when the tenor here, on a conservative news discussion fourm, is such.
It is just such mindless 'policies', admitting of little in the way of judgment calls, that has reduced Officer Friendly to a geared-up bully. That is why parents are driven to counsel their children to avoidance of authorities.
In rural parts of Western and Northern Canada, the RCMP still fulfills the traditional role of 'judgment-call go-to guy'. The RCMP constable is a very important and respected person in every small settlement I've ever been in up here.
Law enforcement is very discretionary in these parts, thank God! I'm sure many rural areas in the States are much the same.
Canadian cities are more down the U.S. road of sudden 'policy' shifts(pandering) caused by political finagling and activist lawyers.