Because there are people out there that if they get hurt on your property they turn around and sue you.
In all seriousness, as true as that statement may be, how have people been hurting themselves with lead sleds? This question isn't just directed at gemby58. If there is such harm coming from the use of lead sleds I would like to know what type of harm it is and how to prevent it. Especially if people are afraid of being sued for allowing other people to use them on one's own property.
