What about the electronic "level"?
I just had a situation today, testing my load development @ 300.
I am sure that I locked my rest for bubble level, integrated into the scope mount (ARC M10-L) - and double checked with my reading glasses, and put the glasses aside...
Realized already late that the Bench top plate was throwing my rest around - of course the bubble level.
I have a full drawer of traditional spirit levels, bigger smaller faster slower, but like today... dark sky, raining, I am looking through the scope no reading glasses to see the bubble... I did not notice on time my error.
I will be looking now for those electronic gizmos that flashes or changing colour or beeps or I don't care how to warn me for canting error.