Love the lurker success stories, welcome aboard moose. There might be a less devious reason than potential rent increases. I have not read any analysis that forecasts serious rent increases in the next year so there may be another reason. Certain properties can atract difficult tenants (beaches, colleges and other areas with novice or yahoo renters) and it is more difficult to evict those in a 1 year lease for conduct issues. If renters seem to stay anyway and rentals don’t sit vacant the lease doesn’t protect the owner, the market protects the owner and the lease protects the renter.
Another theory could be a planned rennovation, contractors are desperate for work and offering great deals, it’s a good time to revamp an aging rental property. Month to month gives them the ability to toss out or move tennants between units during the rennovation if they do it in phases or segments with the renter having no recourse and then they can raise the rate on revamped units.