Cracks in fuel lines.

The shop said that in the attempt to replace the air filter 1 or both fuel lines were either disrupted or cracked. Yes I know the air filters on this model is difficult to remove, that why I took it in to be done. I do not know if the lines were removed. Yes I realize I should have taken it back, but I was trusting in the work performed, and the smell of fuel was once in a while not all the time. I thought it was possible that the mechanic that moved my vehicle in to be serviced may had some fuel or what not on their clothes and got it on my seat cover. I had NO IDEA this would happen. The vehicle was taken to Walmart for the oil change and to have the air filter changed, I had Walmart service this vehicle before at another location with out any issues. I trusted Walmart. And yes, the adjuster will probly still try to put some liability on me for not taking it back right away, but there again I was trusting that they knew what they were doing. But what I am really wanting to know is. If the lines were cracked would fuel leak from them right away? Or would it take some time to get a leak? Like, if the pressure of fuel going through the lines while cracked and heat from the manifold would eventually stress the lines further causing them to expand and cause them to leak? Regardless of the timing, the tech that worked on my vehicle caused damage to the lines causing an eventual fire.