If I pass parameters to a function that doesn't take any, I should get an error

Summary: Inspired by _textLength producing weird results , where Alexx wrote _textLength(Notes), and got mystifying results; the problem was that _textLength didn't (at the time) take parameters, so that param was being ignored silently. This shouldn't be silent -- it should be an error.

Can we automate this, down in the parameter-processing code in Signature, so it only needs to be written once? Is the parameter-computing code ever called when we are in a function that doesn't take any params?