Crab, I appreciate what you're saying, but without good reason it is not within the remit of any rank and file employee to withhold permission to fly.
I agree that the early departure of the dash was probably intended to beat any attempt to recalim debt, but without a specific instruction to detain (impossible to issue without knowledge of the impending cessation of trading) the ATC staff on duty, the only ones apart from FS who could have prevented the departure would have been powerless however much suspicion they had of what was afoot. The blame rests fairly & squarely with EM management for those tactics even given the naievety of the IOM government.