Am I wrong here?

i sell alot of round bales of hay to many different kind of people.

I used to fall into the ... i will be back in a week to pick up the hay with the cash ... Meanwhile i would have 50 other phone calls waiting for this first guy .. Guy #1 does not show up in a week and the other 50 people went somewhere else to get their hay for the year. Then i am sitting on hay in the spring when nobody wants it.

Now i tell them ... If you have cash in your hand ... i will hold on to it for you... If not .. then they guy with the cash gets it.
Thats seems to make people squirm out of deals or race to get the money.