Once you make someone a paid employee if they are on the property and are working they have to be paid. Over the years I have seen this come up at several places and even the signed agreements don't hold up when the Labor Board gets involved and eventually they will. I will not mention any names but at least 3 places I have worked at got tangled up in that mess and they had some high paid legal teams that could not beat it. They even had to go back and pay employees for work from several years back, some where even gone from the company.

Agreed that, for all the above reason, this can get too messy to be satisfactory.

The only time I've seen something like this work is at a non-RR museum where one member had the specialized knowledge and tools to do a specific crafting job, and the guy could only find the time to do it by the time mandated by a grant by taking unpaid leave off of his regular work. As I recall, they signed a contract for the guy to take three or four weeks off of work, paying him much less than a pro shop would have charged but enough to let him take some time for work and still get a paycheck, and paid him a flat fee for the work.

An independent contractor for a single project is a whole different situation from a regular part-time or full-time employee, of course, and I suspect it has little to do with what the original poster was confronting or discussing.