In the case of operators filing multiple flight plans for the same aircraft registration, the following could possibly be argued as salient from the UK AIP.
ENR 1-10-4
2.4 Changes, Delays or Cancellation of a Flight Plan
2.4.1 It is essential that ATC is advised of cancellations, delays over 30 minutes and changes to flight plan details. A second flight plan cannot be used to amend the first. The original flight plan must first be cancelled and then a revised flight plan filed.
If it is the same aircraft, then filing a second plan without a cancellation of the 1st plan beforehand
is, in my view, amending the first, but leaving 2 in the system and wasting capacity. And in breach of the AIP.
The Performance Review Unit at Eurocontrol have the mandate to look at these occurences and report on them. What 'teeth' they have to actually then do something about it is unclear.
Eurocontrol PRU Terms of Reference