Naughty horses breaking away while getting on the trailer/busting some crossties for the heck of it/etc? Those are the jerks who run around the property with a flagged tail, riling everyone up and generally causing havoc, and then come running for the grain bucket.
I can think of seven or eight barns in my area (large ones, 20+ horses) that have road front fencing/gates. It is just simply a MUST if you live near a busy roadway. The ones that don't have gates are the ones in quieter areas, where if the horse gets out you deal with some angry homeowners with pock-marked lawns, not dead drivers.
I mentioned it on the other thread, but if a driver gets hurt/killed by a loose horse, the lack of any safe fencing keeping the horse on the property is going to be the first thing that the lawyers bring up.