Three-Day Unconditional Notice to Quit - Parking

[Samantha Chouinard]

A landlord served a   due to"Violating the Lease Terms"  by parking in the correct location. 

This is a three-bedroom home and the lease mentions three parking spaces ( two in front of the garage and one in the garage). 

The tenants have four vehicles so one of the vehicles has been parked in front of the house in a general open area/extension of the driveway during the evenings (when everyone is home). This space has enough to park at least two vehicles and is again directly in front of the home.  There is no "No Parking Sign" in this space. The Lease also does not mention that you cannot park in that space. 

The property manager has been giving mixed messages regarding the use of the space as she has told the tenants that they are unable to park there and should only be used by the contractors when they come, but has also told the neighbors that they can park there if they pay extra money.

My question is, is getting a Three Day Unconditional Notice to Quit an acceptable action for this?