Milled marijuana shoppers are so devoted that Ontario cannabis store proprietor Jennawae Cavion calls them "Shredheads," referencing the popular Shred brand of ground cannabis from Canadian grower Organigram Holdings. Based on past experience, Cavion associated ground cannabis with poor quality, and at first she didn't stock it.

"I hope that infrastructure is put into place so this is avoided in the future, because this is not something that we should, as a private sector, be dealing with when we're dealing with a government entity we should be able to trust that our data is being taken…

The small packages have been "desperately lacking on our (wholesalers) buy (sheet) every week," said McLean, founder and CEO of Calyx + Trichomes, a licensed cannabis store in Kingston, Ontario.

The action comes despite what a leading industry lawyer says could be a regulatory misinterpretation by the province's cannabis store regulator, the Alcohol and Gaming Commission of Ontario (AGCO).

"The fact is, we've gotten over the hard part now because we have our license. Nothing lasts forever, so as soon as we're able to, we'll be out selling cannabis, even if it's in a modified way like only curbside (pickup) or only click-and-collect.