On the other hand, I've run into a situation recently where this didn't work as I expected. My current project is sold to businesses. When I asked a few of the businesses I was talking to if they would pay me the price I was going to charge for the service to actually make the product, something strange happened. Even though the amount of money I was asking for was quite small this request still went through the entire purchasing apparatus of the business. I figured the manager I was talking to could just write me a check, but I was wrong. Long story short they wanted to own a part of the business if they payed me money to make it, so I opted to not take their check.
I figured this was good enough validation and I'm plowing ahead on development even though I am a tad worried about what my sales cycle is going to look like. But I never would have learned this if I hadn't straight up asked for money before I even built it.