the art of non-verbal communication
The sign says
yet the art work says
The meaning of the communication is the response it elicits, not necessarily the intention of the communicator.
My guess is that Sol LeWitt knew that one of the meanings of this piece would become “climb on me”, maybe it is the message of all public sculptures ( some more than others).
The sign not to climb, the verbal communication, is incongruent with the non-verbal communication, the sign that is the art work itself. Possibly, that’s why people ignore it, or notice it after they have already transgressed! I suppose it’s a lot like “do not walk on the grass”.