I'll bet.

From the sales viewpoint:

You are offering something with a price tag of 0.00. This diminishes the builder's perception of the value you put on yourself and your services. In other words, if you're giving something away, how do the people you are interacting with view you on that issue? Let me ask you this; if a vendor gave you wire on the premise that they got to present to all your customers in the hope of selling components, how would you think of them; a business partner you could grow with or a source of free wire?

From the business viewpoint:

Bad financial mojo. Unless you have deeeep pockets you could not finance this effort. The more you grew the greater your front-side outlay. This would impose a glass ceiling on growth, for sure.

From the practical viewpoint:

Builders that would be attracted by this would more likely (not always, but probably the majority) to be the type you want to avoid.

From the A/P side:

Big plus; there would be no problem collecting payment on the work you had done. :-)