Gas Cap

Yes you have to run a gas cap.  I carry a spare.  You can get black flagged for any fuel spilling, if you get a second for fuel you are done for the weekend.

The only stupid question is the one that's never asked - if you need the information. There are frivolous questions, but that's different.

Often? This is concerning to me. Is a cap or closure checked before going on track - like the wristband? Interesting question to me: can corner workers see what happens on the outside of a turn, like fuel spilling?

Good idea; I'm thinking of doing that with my dd.

I'm in the same boat... if you see fluid coming out of my car... call me in! I've called in a few cars leaking fluid... wasn't sure what it was, but i'm sure that team appreciates being black flagged instead of on fire. Even if it's from a cool suit, I've had a cool suit dump it's contents on a straight, in front of my rear left tire, and I came a couple feet from totaling the car into a wall. Even if it's water, no team leaks fluid intentionally.

Regarding the gas cap, yes you need one, but I don't think losing it in the hot pits is an actual problem? Putting the gas cap on (yelling "cap on") is a trigger for the rest of your team to be able to commence the driver change process... no gas cap, and your team should be frozen and focused on the one person whose adding fuel. Once that cap is off the entire car should be treated as a flammable paper weight. I can't see how it would possible to be lost or forgotten during the process. We always rehearse fueling on friday before the weekend, it sounds and looks silly, but it keeps us safe.

No, it's not a mandatory check like the wristband, helmet sticker, and windshield sticker. When I'm checking cars and drivers at pit-out I'll look (but only look) at the gas cap, but only if it's visible from where I'm standing. I don't do a walk-around of each car as it tries to go onto the track unless I notice something weird as it approaches, like an object dragging on the ground beneath it. I will be looking for anything leaking as the car approaches and as it leaves, though.

I won't touch the cap to check it or to fix it, but I have sometimes noticed an obvious issue and instructed the driver to return to the paddock to take care of it.