I just had my first guest-- been doing this for nearly 10 years!-- have a package delivered without permission (it was already here when I got home, despite some assumptions about Chicago southside, packages are generally safe on porches!).
This has been covered again and again in many threads-- there are many problems, and guests should certainly ask in advance!
My primary issue is residency. Any piece of mail or package with an address on it, can be used as proof of residency. I've had to have the police throw an Airbnber out exactly once, and it took about 6 hours and escalating it to the captains.
In this case, the guest is a three-week stay; in most of the US, hit 30 days and you're a tenant, not a transient guest. Add to a potential eviction, the fact that we're in a city that requires landlords to be registered and permitted etc, and the potential pain here is high.
And mail or packages to non-resident transient guests should always be delivered "in care of" the name of a business, institution or person, not directly-- if you're going to do this at all.