As with everything in life… folk will have differing experiences…
Personally, I try to “do things right”… yes, I know that sounds boring… and in some ways it is.
On the rare occasion that I’ve “broken the rules”… I’ve been on tenterhooks, convinced the authorities are going to pounce and discover my extra packet of whatever… I’ll be marched off to the cells…
Frankly, I decided it simply wasn’t worth it…
and, if the rules are in place for a health/sanitary reason it does make sense to stick to 'em…
There again, some years back I did find myself hurredly munching a ham sandwich just before our car rolled forward to be checked… 
would they have found it ?? who knows… I couldn’t stand the strain… my courage failed me and I nearly choked in my panic…