I have dumped fuel or oil on my pants at least once with every saw I have ever had going back to the 50s. It's not a matter of the type of cap.
as for the flippies: I don't have a problem with them but still don't see the "why?". Looks like a solution to a non-existant problem. I have seen people claim it was because of needing to use a tool to tighten the screw on type. That is the purest of BS. To my mind, anyone applying a scrench to a fuel/oil cap is abusing the equipment - never did it myself and have never had a cap come loose during use.
At least the new caps have abig black mark on them to show how the cap fits right on. Both caps will hve the black bar pointing at the power head when it drops into place, 1/4 turn and close it. Still don't think it is any faster than screwing on a cap which can be done without even looking at it.
Harry K