>>1882951It's a risk, but I expect most used ebikes are functional. Someone bought one and decided they don't like it. They don't use it enough or they wanted to get a better one. Or it's just stolen. (might want to check it against bike registry websites)
It seems like those situations would be more common than someone running the battery dead. You could always buy a new battery if that's the case, but the battery is the most expensive part.