How 'bout this reply (humor only -- DO NOT use)"The landlord believes that "visiting clients" is frequently a euphemism for illegal activity such as drug-dealing or prostitution, thus "visiting clients" are NOT permitted at any time.

Liability out the wazoo-- roommates bringing guests over, complete strangers living with each other (alcohol, assault, drugs, etc.).

Turned out to be a drug dealer...

Kicking on the door and/or adjacent window until a tenant or resident drug dealer opens the door for you was pretty much the only way to gain access.

I wouldn't worry about it, unless it seemed like something else weird was going on - like you though it was just a place to manufacture drugs or something.

My neighbors said they are 99% sure there is some sort of drug operation that the tenants are doing out of my house in Hawaii.

Even though I wanted her to stay because she paid on time, I found her to be very demanding (she did all sorts of bizarre things like claim the neighbors were drug dealers, stalking their activities, hassling others in the community, continuous repairs - I have other properties and no one is as high maintenance as her) and I was upset at the state of my newly rehabbed place.

You want to know the process going in when the tenant is selling drugs, not complying w/ the lease, abandonment, non-payment, etc. 

No one is on a lease it is a self run sober living home for people recovering from drug and alcohol addiction.

Find out she has a serious drug conviction and tell tenant she doesn't meet standards and she must go.