I agree with Retired Can Soldier - she purchased the property knowing what the current tenants were paying. Obviously, it was a good deal otherwise, why would she purchase it to begin with? If the rents were too low, and the ROI wasn't positive, why would she have made the purchase to begin with? She's just being greedy and yes, trying to "get around" provincial laws. It the Province allows a % increase on a yearly basis, then she can raise the rent accordingly.
Insofar as landlords and tenants, there has to be protection for both and, if Alberta is any indication, it's rather difficult to evict someone without having to go through a heck of a lot of red tape.
On the other hand, landlords also get stuck with the bill of cleaning up after people to "vacate" in the middle of the night leaving their crap behind and rent owing so it does go both ways.
It's not an easy business and I know I certainly wouldn't want to be a landlord. We did consider it for a minute at one point, but decided it would be too much of a hassle in the end. Too many horror stories and, there are those who take no responsibility for looking after where they live because "it's not theirs" so who cares right?
If these people are good tenants, why would she want to get rid of them? I'd want to keep them so it sounds to me that she's simply being greedy.
JMHO