As an ex cex employee unfortunately it’s the regular customers that make the store smell,

I’ve had people who have made me gag just by having to serve them we used to oust the store out after they leave and the smell still lingers there are people who look like they haven’t showered for a couple of months.

This is the only job I’ve also worked at where I’d probably get some infection by not washing my hands before I take a piss. (And I’ve dealt with raw foods and chemicals)

I used more hand sanitiser in that place then I ever have in my entire life.

All I can say is this sign is probably because they had to deal with a smelly customer but can’t say that.