The city has a law that an accessory building in a residential neighborhood can not be occupied for overnight sleeping arrangements. 

For the most part, i use my own funds so it helps me sleep a little better at night knowing that in the worst case I can hold out or turn it in to a rentalMy golden rule of flipping is....."

You could buy some REITs at a 6% tax-free (TFSA) income yield and go to sleep. 

In my market, it's a huge bargain for groups/families to rent for a unit that sleeps at least 4 people.

As soon as upstair’s lease ran out, I kicked her out because “I wanted to do some renovations,” DEFINITELY NOT because her kids were disturbing the peace.

If the guest disturb your neighbors in the middle of the night with music or anything, or smoke, or drug or bringing prostitutes to your place, etc... there is no compensation and basically no penalty for the guests.

But Id like to sleep well at night.

Some would consider this overkill, but it’s what I need to sleep at night.

Just because you have to have valid reasons to evict people, like not paying rent or causing damage or disturbance - or some other lease violation. 

I like the bio hazard idea :-)  A sign like do  not disturb the tenants, or this property is under constant surveillance can help.