If you want to pay a request that is higher than your funds (you click on the link), only the wallet opens but there is no error message like "you don't have enough money to pay for the request"
Many times people on Twitter wanted to request 1000 IOTA, but accidentally requested 1000 Miota (also a problem maybe). So I opened the link and didn't even know why the link did not work.
But checking the link I realised they wanted to have too much money...