Tell you what I do when I fill.
Remove my Nipple cover (nice XSV, highly recommended).
Check Nipple...
Check fill coupling.
Hold fill hose and blast a quick shot of air through it to blow any crap, water, oil out. On the system at my training ground, you can do this without holding the hose, as it has some sort of valve in there that requires back pressure, before it will fully open, so the hose wont whip around...also, it wont flash fill...even better
Connect Coupling and double check it is fully on (been there, done that Cocker didnt like it)
Hold marker by feed neck, barrel etc and TURN MY BODY AWAY, so I'm not prone to the bottle.
Slowly fill bottle.
How the hell are you supposed to cater for c0cks who put mineral oil in the coupling?
I think, they should have a series of metal boxes, with high sides, or that have an opening pointing away from the players, that you put your gun/bottle in before you fill it.
Yeah, might take all of 30 seconds longer but the safety side of it...well.
If you add all those 30 seconds up, over an entire tournament season...it will still equate to less than the downtime involved with an incident like the above, or worse.
I don't think the seriousness of the potential hazards are fully covered.
EDIT: Also, whoever said about the heat that air gets too when it's compressed, your right, but its not being compressed, when we fill our tanks as such, but the movement of the air (very fast through small holes) creates heat via friction.