For those of you not resident in the UK I’ve adapted a number of British road signs, this one has no adaptions to it at all, apart from the meaning.
Assuming that you have been buying stuff “just in case”, it may be a lesson in checking at the back of the fridge. I seem to remember making this joke when teaching my daughter to drive ( not much teaching but plenty of left leg brake exercise for me ) and I would say “Watch out for the taramasalata when you go over this next hill in the road”. She usually just told me to shut up with my “Dad Jokes”, but it helped calm my nerves.
Steer clear of hidden dip and people. Stay well.