I suspect restaurants have notice prior to health inspections. Think they get warnings in most cases before cited or downgraded. This coupled with low wage employees results in horror stories. Thankfully most of us have suitably robust immune systems and survive.
Oh I forgot other tales.... finding a large roach in frozen container of supermarket sourced manicotti ages ago. Went to a mom and pop restaurant in NYC with a window view of kitchen via hallway to restroom. Noticed a cat walking along a narrow table near sink and prep area. A cat!!! Only thing worse is contemplating the possibility of its litter box in the kitchen lol.
LOL!! Yeah-- they usually at least have a window of notice (from what I understand)...Health dept states that there will be an inspection at some point in the next 2 weeks or something (my bosses at the time seemed to know because they would usually tighten things up around that time). Plus, even when they do show up, they usually putz around at a booth with a clipboard or speak to a manager first, so everyone in the back can scramble around and try to fix the obvious stuff.
Sadly, many of the infractions aren't super obvious unless you observe long-term (like a fly on the way). So even when they come, they are going to see things like.."chicken was stored above the lettuce" or "dishes sitting in sink" ,but rarely do they observe employee behavior (unless it's something crazy obvious, like lack of gloves on a prep line--and you can always tell it's an inspector because of their laptop or clipboard)....and they never come at closing, which is when a lot of sketchy stuff happens.
That cat story is INSANE....!
OH---The ice machines!! Those are nasty...people scoop out of those things to fill the troughs etc-- and hands are not usually very clean. ALSO-- Both my sister and I worked at places where we saw employees drink from a cup they brought or a large plastic one....and then USE THE CUP TO SCOOP DIRECTLY FROM THE COMMUNAL ICE MACHINE! ...
People also used to use their hands sometimes to get a chip of ice and throw at a co-worker (as a joke)...but hands in the machine...
Redi-whip--- people used to spray that into their open mouths...
Those soda machines--- also nasty (people refill cups that people have already drank out of and when you do, it splashes back up onto the dispenser). I remember at one place we got dinged for that on an inspection and were told to use new cups every time, but that lasted for like a day....
Last one--- the lemons, cherries etc...those "garnishes" omg.. This applies to every single restaurant where I ever worked (nice places too...)
1. they sat in a tepid pool of what was ice at like 8AM but is melted by 10...
2. The tongs were always getting dropped or moved or in use (or left in the dishwasher from the night before and never returned to the station), so 50% of the time, people quickly plop them into drinks with their bare hands!!! Hands that had touched all sorts of things--- like other people's dishes...A waiter will move plates/wipe a table and immediately run out new food as long as their is no visible soiling on their hands that cannot be wiped on an apron. Plus, it gets really hot, so people are always wiping their faces with their hands...
TV remotes are infamously as or more filthy than toilet seats. 
And those glasses/coffee mugs? Many properties clean them in-room with cloths. 
I'd never trust bathroom counters and would lay out a series of Kleenex before setting out toiletries. 
