Our connection to RESTBase is over HTTPS, so I'm guessing this is some sort of client-side tool.

I think it is some client side tool.

possible solution:
for(var i=0;i<IGNORE_PLUGINS.length;i++)
if ( navigator.plugins.hasOwnProperty(IGNORE_PLUGINS[i]) { disable VE }

or is there a already something similar?

Maybe we could look at something like that... The code wouldn't look like that, but perhaps something that checks through navigator.plugins?

Anyway, first we need to find out what we're actually filtering for.

I asked one of the editors who had such problem:
this is due to some client side program. (http://www.rimon.net.il/he/%D7%94%D7%AA%D7%A7%D7%A0%D7%AA-%D7%AA%D7%95%D7%A1%D7%A3-%D7%9C%D7%93%D7%A4%D7%93%D7%A4%D7%9F )

Anyway, I'm taking back the idea of using navigator.plugins - this is bad idea, I don't think we would like to maintain list of bad plugins.
Maybe some very simple expected CRC or length of the edited text on the beginning of editing article can be calculated and compared to server side calculated value and if they don't match we know there could be problem...
I'm pretty sure it doesn't worth to have such feature for this specific program, but if there are other plugins that behave badly maybe it is option.