Don't think I have seen these signs before.
there are quite a few around!
Could do with a few of those signs and some super-bright lighting at Pier 3, at the bottom of the ramp leading up to the taxi stand. Bit of a hidden corner and clearly used as a toilet at night, no doubt the appointed toilet for the booze shack on the other side of the stairs. Quite disgusting in the morning, particularly Monday morning!
My old car park had these... Big cockroaches as well. The two may have been related.