Yep.
Last Sunday my 13 year old daughter was cutting the grass with our riding mower. After a few hours she came in the house and said, “The mower ran out of gas.”
I didn’t think anything of it at the time. The mower sat there until Friday, upon which I finally got around to filling up the gas can and filling the mower with gas (see my related pit thread). It was then that I discovered she had left the mower’s ignition switch in the “ON” position after it ran out of gas. Battery was dead. Which meant the battery was dead for a five days. 
Even though I have an external battery charger, I didn’t even bother trying to charge it. A lead acid battery that remains in a discharged state for more than a day or so is likely toast. Went out and bought a new one.