There is a lot of stuff that seems deceptively easy to administer. For example, I am trained to administer dextrose 50%/D50 through an IV. A nurse here on ZS said that they were uncomfortable with administering D50 because there is such a high potential for necrotized tissue, and I certainly agree - as a II, I'd never give D50 unless we were en route to an ER, the vein was 100% patent, and my paramedic or medical control told me to do it.
Just because someone carries D50 in their FAK doesn't necessarily mean they would administer it in that form. Most advanced FAK's and trauma kits are space limited, so rather than carry a bunch of indivdual 250cc bags of D5W in addition to NS, it simply makes sense to carry more NS and a single 50mL vial of D50, then dillute it 9:1 with NS to make D5W as required.
I was pretty surprised to see ET tubes and IV & IO sets in some of the kits (let alone morphine, atropine, naloxone, needle decom kits, and other stuff). In my state you have to have a physician's license to buy those kinds of items, and I thought that was the case all over the US, but apparently some smart folks have persuaded their personal physicians to give them prescriptions, which is great. As numerous people on this board have stated, in a Katrina-like situation, you will probably be able to scare up a paramedic, nurse, or doctor who DOES know how to use your painstakingly assembled badass FAK.
It is WAY too easy to innocently overstep your bounds in an emergency situation and not realize how much harm could potentially be done. In my opinion this temptation to ACT NOW could potentially be very high in someone who has access to equipment that is beyond their scope of practice.
I can only speak for myself, but having a FAK with most of the more advanced items that you mentioned presents no more temptation for me to "ACT NOW" and use them in a non-PAW situation than does having a couple thousand rounds of 5.56 NATO on-hand for my AR tempts me to take out the first obnoxious coworker that pisses me off.
Without a drug bag full of fast acting sedatives and paralytics available I doubt anyone here would attemp to perform RSI on a conscious PT even in a PAW scenario. If on the other hand a loved one in the PAW is unconscious due to an inability to maintain a patent airway or aspirating stomach contents into their trachea and medical asistance is definitively unavailable, then the risks associated with intubation and "do no harm" somewhat go out the window given the alternative of not taking any action.