At the bottom of the rate sheet you find lock requirements and deadlines as well as lender fees. The program requirements often change without notice. Some brokers get rate sheets from over 100 lenders. Imagine how much work it is to look through 100 rate sheets. Obviously, nobody ever does.
Most brokers work with just a few reliable lenders on a regular basis.
I used to subscribe to an on-line service listing the programs and rates for over 80 lenders. That service helped, but wasn't without flaws. When rates moved during the day and we got a 2nd round of faxes with rate changes, the on-line service lagged and didn't have the correct rates. Often the program guidelines were incorrect. But every time the quote was too good to be true, it wasn't true.