Yes Face drivers who tailgate and travel too close are generally pretty dumb in most respects.
Tailgating saves fuel.
I like it. (Plus I get home quicker).
Contraflow:
A quick tap of the brakes is usually sufficient to remove that troublesome set of mirrors at the end of your trailer.
had this done to me last year , when after 9miles being stuck behind a t*t in the middle lane trying to over take another truck for 9 miles 52mph 
, i flashed him out of the way as he wasnt ever ever going to over take him, so he stamped on his brakes , i back off some more flash flash, knowing he was going to hit the brakes again, sorted he’s slowed himself down that much, i could then inside lane and up his inside safely, wave at him and on my way, and he was still in the middle lane overtaking nothing for the next 2 miles
this was 2am in a morning and he did have a hi viz on 
Shame on you Si. 2am in the morning? That’s what lane three is for! 
eagerbeaver:
Tailgating saves fuel.I like it. (Plus I get home quicker).
If you could get seriously close (within a couple of feet) both vehicles would benefit from better economy; If for instance we took a front high cab following very closely to a trailer of the same height, you would remove the drag created by the vortex that normally exists behind the trailer of the lead vehicle.
With some very basic assumptions and back of a ■■■ packet calculations, i would expect that when sitting on the limiter on a level road, the tailgating truck could improve mpg from 10 to 14.3 mpg and the lead vehicle would also see an improvement from 10 to 10.9mpg.
Of course any savings on fuel would be lost in collision damage and fines.