Good advice. I'd add that if you don't think your boss/manager would stick up for you if it ever came to that I'd say get the ok from their boss too. If everyone up the chain says "screw it, we're not paying that much for photoshop, my cousin gave me a cracked cd" just make sure that they know what you're doing and that they know that you know.
And of course not to make the point to which you imply but there *are* a significant amount of free and almost-free software packages available for many uses. If they *have* to have photoshop then make sure they know what Photoshop costs and that the cost can be paid by the employee, the company, or in bad karma.