[Alan_Dillman]

That's similar to how it works in my Canadian workplace. My employer has a pool of workers, and when a project is coming up, the manager phones around and fills his or her labour requirements. Lots of us work secondary jobs too, and this is both reasonable and understood, and a "no" or even a series of noes to an offer won't put you on the street, though it may lower you on a particular manager's call list.

Its like renting yourself out. You don't feel owned, and nobody feels they own you. Its great.