Way back my buddy and I went for a ride to a friends house. When we left he noticed his stock fuel line had hardened in the months we had been riding these 'new fangled things'. I had cracked and leaked all his fuel out. We rode to the gas station, he peddling, me towing him when we could do it safely. We repaired his fuel line with a Bic pen, he filled up and we rode ~6 miles back to my house and we put some real fuel line on his bike.
At the time, we thought it was the ethanol in the gas that had caused the fuel line to harden. Turns out we were probably correct. lol