Spike is perfectly willing to leave without Sunshine's bag if it will get him out of here before people besides Sunshine start touching him. It's only it's placement by the door that saves it from being left behind.

He moves Sunshine along as quickly as possible. "Say goodbye." He grabs the bag and waves in a vague approximation of a goodbye. Once Sunshine says her drunken goodbyes, they're out the door.

Now there's only the daunting prospect of getting back home.