Keeping the loaders off track and using cranes to cherry pick a car up from behind barrier maybe? Tbh hitting a loader with a skirt on it would still be pretty serious.
yes, but less serious than going under it, that is the real danger and what maybe happened here, a car getting wedged underneath.
Think back to Silverstone, there was metal there but the danger was because one impact opened a hole, the next car may get wedged in it, with open cockpits any kind of car going through something like that can lead to heads coming off, literally.
Realistically it's again more about making an area safe. I'm about 98% certain that even if Bianchi went off and smashed into Sutil's car the damage/danger would have been a fraction of what has happened. The main difference is the momentum involved, Sutil's car wouldn't be so heavy it would just stop a car dead and both would have gone into the barriers absorbing much of the energy, a ridiculously heavy truck/tractor/whatever just stops a lightweight f1 car dead, no energy absorbed by materials that give way or attempt to deflect the impact to allow the car to bounce away, nothing. Hell, a huge heavy machine that stays behind the barriers with a winch that marshalls attach and simply drag the car around, may damage cars more but would be less dangerous.
The safety car is almost irrelevant, it wasn't 100% safe to leave Sutil's car there, but hitting Sutil's car vs hitting a JCB of any size or shape is night and day. Putting the JCB out without a safety car decreased safety massively in a known corner that is often a problem when it rains and at a time when rain was worsening, track was worsening you have the highest peak of aquaplaning and danger. Under those conditions the JCB, with skirting installed or not, should never ever have been out there.