I just can't see rats in a 900k neighborhood, but maybe with California's insane priced-out market 900k is a rat-infested neighborhood!

My properties are located in a drug infested ghetto.

I chatted with the pest control guy who says some of the class A places he services have that issue along with pest issues.

Also, the friend may not report problems with the property because they don't want to "be a pest" therefore causing some deferred maintenance.

That reduces possibility of interior pests.

This is the first month that there excuse holds any weight, the home became infested with bedbugs which cost them around 600$ to treat. 

Also, pests love dirty rentals so you can reference that as well.You don't want to perform these all on the same day or time of month either.

Otherwise, they will start manufacturing supposed mold issues or pest issues, and they may even cause damage and then say you're neglecting the property and it's uninhabitable and call the building inspector, etc.So, maybe there's a middle ground. 

For instance we’ve got a bees nest and I’ve already arranged for pest control to come in less than 4 days and notified the tenant about this and still they call/text 12 more times to bring the issue to me.

Sometimes it looks good, then three months later when they move out the place is completely trashed and bug infested, as @Dennis M. noted.