He checks for lint blockages but there are none.

Sharpened the blades, made sure the rotors turned adequately, but anything more than a fork full of spaghetti meant a total blockage.  

We were not ever able to get the object out ot the toilet so therefore were unable to identify the exact object that caused the blockage. 

I just had a sewage line blockage that caused a backup into on of my basement bedrooms.

During that inspection we are looking for damages that the tenant will not be charged for when they move out, and we always have them check all sinks, toilets, tubs, for proper drainage.3) Sometimes, a partial main line blockage would not be evident, either during turnover prep or at move-in inspection, due to the distance from the fixtures.

"on premises blockage" of a sewer line.

Usually depends on two things: 1) What caused the clog, and 2) How your lease reads.For example, my lease says “Tenant shall be charged for repair of drain blockages or stoppages, unless caused by defective plumbing parts or tree roots invading sewer lines.I have had tenants call me about clogs that were found to actually be caused by tree roots.

Specifically regarding plumbing you could add (depending on your State or Local Laws) "... unless determined by repair person that such blockage occurred during the time Tenant controlled the Premises and due to some fault or negligence of Tenant, specifically excluding blockages caused by roots or backups from the street..."

The snake cam revealed a blockage and the culprit was...feminine hygiene products.

Nothing goes around them and things get bad real quick.Every time I get a blockage in a unit that can't be plunged, we pull the toilet and try to fish it from the bottom side.