I'll not comment on the prosecution or acquittal. But I would say;
1) my (limited) experience of a/c fuel gauges is that they're much less accurate than car gauges, but it should be remembered they are (in light aircraft) usually only a gauge, NOT an accurate meter.
2) I once flew a 3hr round trip to Norwich and back in a C150 with the (standard) fuel tanks topped up on the outbound leg. 2/3 of the way back, one gauge read zero and the other only 1/3 of a tank. Based upon the club's approved 18 litres per hour fuel burn figures, the 150 should have around 5 hrs endurance. I carefuly did all the sums - twice - but was still concerned by the low gauges on the return leg. Upon landing and checking the tanks, each had over 1/3 fuel left - as I had expected and calculated, despite the fact that the gauges now both read almost zero. I could easily have been tempted to divert or make a precautionary landing under power if I had trusted the gauges instead of my numbers, BUT on the other hand, how can I be sure that there is no invisible fuel leak? I was operating the a/c nowhere near it's maximum range or endurance, and yet the gauges were so far out as to make me think something was wrong. I would add this wasn't the first time I had flown the a/c but it was the first time I had taken that particular C150 across country as opposed to toodling around the area, hence I wasn't familiar with the way the gauges read in that a/c.
I guess the moral is do the numbers, check the numbers and double-check the numbers, and never rely on fuel gauges that could so easily under-read or over-read.
As for the court case, there but for the grace of God go many.....