The first is the head detail. The wall stops at a suspended ceiling and the ceiling void runs continuous over the top of it. Sound crosses through the void, over the wall head, and down into the next room. A wall that is sealed to the structural soffit, with the ceiling built tight to the wall, closes this path. A wall that stops at the ceiling grid does not.
The second is the floor line. A continuous screed under both rooms is a flanking path in its own right, and a skirting that bridges the wall base is a leak. The isolation detail — a break in the screed, or a resilient layer, and a skirting that does not cross the joint — is usually designed and then value-engineered out.
The third is the service penetration. Ductwork, conduit and plumbing cross guest-room walls above ceilings and behind joinery. Each penetration needs a sealed collar or an acoustic barrier; in practice they are often left as holes because nobody owns the detail.
The fourth and fifth are the door and the socket. A hotel door set is the weakest element in the wall by a wide margin, and it needs a drop seal, a perimeter seal and a solid frame, not just a heavy leaf. Back-to-back sockets in a party wall are a direct path: offset them, or put them in separate stud bays, and they stop being a problem.
The pattern behind all five is the same: the wall is designed, and the interfaces are left to the trades. A hotel that measures well has had those five details drawn, priced and inspected.