By nature of the way many of us use them, these machines are "unsafe". We have built a culture that is so risk averse that they are afraid to do anything for fear of getting hurt. We have trained up a generation that has not been taught to properly recognize and analyze risky behavior. Today, we live in a society that seems to believe that there is a "re-spawn" button on human life and therefore such people must be protected from EVERY possible danger which might exist. The old saying still applies, "It is impossible to make anything"Foolproof", since fools are so ingenious."
I still have the sleeve in my fuel tank. but frequently "pack" the tank by placing the right front wheel on the ramp while filling the tank. (Yes, I have a PIONEER 1000, but the same discussion applies). I can "pack" in almost an extra gallon of fuel doing this. I never "pack" the tank and then park the machine. After "packing", I immediately hit the trail and the extra fuel extends my riding time significantly. I also have the tank vent lines extended so that the vapors from the tank escape into the free air, instead of under the seat as they do with a "Stock" 49 state PIONEER. I also went further and placed a flame arrestor screen on the end of the now raised tank vent.
In my mind, it is more likely that you will get a fuel tank contaminated with water and dirt then be left stranded from the poorly placed OEM Vent (on the PIONEER) than you will by somehow having a fire. I carry a fire extinguisher as well, just in case. How dangerous is it to be stranded in the middle of nowhere, either from running out of fuel or having a tank full of water? How dangerous is it to carry extra gas cans? In the south we have "mud dauber" wasps who love to build in the ends of open hoses. I have seen the fuel tank vents stopped up with such nests, this closes the vent and eventually stops the machine.
In my opinion, this discussion is necessary so that people who choose to make this (or any other) modification or who, like myself "pack" the tank are made aware of the possible ramifications of their action. The FIRST rule of safety is to be aware of the risks involved in any action. Do not make ANY modification to the machine without fully investigating and understanding how such changes can increase your risk. Weigh the risks against the benefits, if you do not find the risk acceptable, go by the book, don't change a thing from stock and live your life.
Just my 2 cents.