I promise I didn’t plan it this way – if I’d known about the article I’d have included it in my post earlier this week – but there’s a good short piece on pseudo-writing in New Kingdom Egypt at Past Horizons, about work being done by Dr. Ben Haring. At the workers’ village of Deir el Medina, one of the richest sources of our knowledge of daily life in the New Kingdom, ordinary (cursive, hieratic) script is found alongside a nonlinguistic system of marks used by tomb makers as personal marks of identity, and many writers were familiar with and used both systems, thus refuting the notion that pictograms are supplanted once phonetic writing comes along. The question of influence of hieratic script on this system of marks, and vice versa, is a rich line of intellectual inquiry.
Glossographia 
Does this research influence you thinking on Vinča signs and Harappan scripts?
There has been some research claiming that Harappan writing is not writing at all, e.g. Farmer, Sproat and Witzel 2004 (http://www.catshaman.com/essays/harrapanl.pdf). It’s not resolved at all, but this is a different sort of claim than the claim that it constitutes pseudo-writing (i.e., designed to look like writing even though not actually communicating any linguistic information). It’s possible, I suppose, that the Harappan symbols, if they’re not a script, were designed in emulation of Mesopotamian scripts, but I don’t think there is any reason to believe this to be true other than the fact that we can’t decipher them.
As fro the Vinča signs, these pre-date any known well-accepted writing system by 2000 years, at least, and thus they can’t be pseudo-writing. They may be something else (proto-writing) but that’s a different argument altogether.