Reno: What about designing a lighting layout for a kitchen? They could hire a designer or an electrician. Should the electrician provide the design for free? The designer wouldn't.
By the time you get the specs for the lights and discuss all the options with the customer, you could have a lot of time invested in the job. It would be a shame to have the customer give your drawing to your competitors.
If you hand over too many details, it will eventually happen.
Maybe it's a question of wording. Your quote needs to be specific. It doesn't need to be too detailed. I would include "vapour barriers" in the quote, but not how I get them around a fished outlet.
