I'm in the camp of a discount or the like.

Please be aware that your lease does say (whatever your lease says about limiting overnight guests for whatever period of time), so if you choose not to go ahead and put him on the lease, he won't be allowed to stay beyond ___________"  I wouldn't start a new one-year lease, though, in case they end up drama queens. 

San Diego allows some parking overnight in public parking lots. 

Whenever the students moved out of housing, all kinds of junk magically appeared on our property overnight LOL.  

We tried to stay overnight while we were cleaning initially, and ended up getting a hotel instead as our lungs felt like we smoked 2 packs of cigarettes after several hours in the home, even though the lady had quit smoking months before.  

My tenants wanted me to put them in a hotel for not being able to use the water in the kitchen for 12 hours overnight (still fully able to use all 2.5 bathrooms and laundry facilities).

Discover gave me an instant approval as well and overnighted the card. 

I think you should consider starting up a summer camp.  

Camp out. 

But, when the market crashed even here in Silicon Valley, we lost 25% of our tenants overnight, other apartment complexes with lots of amenities had giant signs on the buildings that said no credit checks, free first month's rent, no security deposits - not kidding.What we learned was that student tenants are crash-immune.