I tell this story a lot. But I think in the time of smartphones and such it also represents the only real secure site I thought was truly secure from what I knew of it. This was before smartphones were common, but I think it was ahead of its time in that way. I worked for a company that occasionally would service some of our hardware onsite. One customer was a company that did a lot of work for the military and they…
The boindfolds seem like extra work, I would just get a SUV and totally black out the rear, or well, put in some seats in the rear of a delivery van. But I guess the boindfolds also had a psychological effect of "we mean business".
If you lack out a special cabi area for a vehicle, either you are leaving them to their own devices in that area, or limiting the senses of your own staff you put in to watch them.
Finally, it's just a lot more expensive and cumbersome to have a large piece of machinery like that, and more likely to fail. What happens if the engine fails? Do you need a spare now? Using a blindfold as backup means that a blindfold is sufficient, so just use it and any vehicle now works.