@Allison Panila
What I haven't seen brought up is the kind of relationship your friend has with the landlord.
When I lived in an apartment complex, I made sure to have good relations with all members of their staff. I also think this got me prioritized when bringing up repair issues. When I left, they didn't even do a walk thru and I got my full deposit back, though that was due to me and another Soldier putting out a houseplant that caught fire on a 3rd story. I might have been the only person to have a fire extinguisher, there were 0 in the common areas.
Sales training has taught me that if someone likes you, they are less prone to make trouble for you. Landlording could be different, if they get the vibe that they can run over you from friendliness.
I cannot make many accurate assumptions about either group. The landlord should be explicilty clear in the contract to define 3 visits (education point for me, thank you). The tenant could be having them over 3 nights or 21 nights, that point hasn't been made clear to me.
Raising the rent by $50 for more visits seems reasonable, (legally, no idea). There's a poorly written clause, I'd abide by it just to get the threat of eviction away.
Human beings are emotional creatures capable of logic, not logical creatures capable of emotion.
It's bad practice to live in close proximity to someone with ill will towards you.