Top Bunk Maastricht has the capability to send such messages and a/c euipped to receive it are so indicated by the system.
Farmer1 Two or three controllers per sector at Maastricht depending on traffic levels. Unassumed traffic, i.e. traffic in or about to enter your sector but not yet in contact, flashes. When in contact an Ässume"input is made which increases the brightness of track and label information, also co-ordination info is then displayed.
It is, of course, possible to "assume in error" as this is all done by mouse clicks on a 3 button mouse (due to stupidity and damaged nerves in right hand I was forever doing this) and then theprevious sector believes the flight was transferred until too late and he is out of range, however another a/c can be used to relay a message. This doesn't happen too often as most flights require some vectoring or level change in Maastricht Airspace. That said, and looking at dep. and dest. there is a possibility that the flight had been re-routed by flow control to avoid Belgium, but was still given a shorter than normal routing along the Belgian Dutch border and each sector believed he was working the other. Not very likely though.
Hope this helps, all a bit vague, as I'm no longer working there.