Strong oral cannabis may well appear similar to opiate OD to the unwary medical practitioner.

I find it quite likely that a bunch of people ate some hash brownies that were too strong and couldn't cope. Or the people around them misidentified their state and decided to help prevent them from dying of an opiate overdose. Which could be seen as reasonable.

Concerns about potency of cannabis edibles have already been raised in the past couple of weeks, IIRC.