prob used officially in documents/ records but just not reflected on signboard (but yah which i agree also shouldn't be allowed, wat if ppl wanna report food poisoning etc then how to indicate?)
sinkies are familiar with 3-letter acronyms and abbreviations. all stalls and eateries should have unique alphanumeric identifiers such as:
knn6969
ccb1234
pcb3693
lkb5678