Despite proclaiming its governed be law and order, the arrest of Mrs Meng is technically illegal to begin with. She was technically in a grey zone when she was arrested, which means she was technically on Canadian soil when she’s waiting for transit flight to Mexico, but she never gone through the custom (custom transit area at international airport is bit like no mans land), so legally RCMP has no jurisdiction to arrest her.
However, Canadian border services has jurisdiction over where she was, but CBSA can’t carry out arrest over the US request, so CBSA detente her for an extended time and perhaps illegally requested informations from her and later turned them over to RCMP. But given she probably never intent to go through the custom, so this is where the dispute came whether her arrest by RCMP is even legal.
But given the same year 2018 after the 5-eyes Halifax security conference, a joint effort of all out frontal assault on Huawei started from the 5-eye alliance and till her arrest in December of the same year, most rational people can probably draw their own conclusions on this affair.