I think if you read the communication released by TUI and by their CC it is clear that they are taking the 50 TCX skippers on because they don't have the training capacity to promote enough FO's into the left seats created by the sudden rapid and unexpected expansion of their s20 operation. Now, in a balanced world the TUI FO's in the command pool may feel aggrieved, but had TCX not gone bust it is likely that the same number of them will have got upgraded as will now. Handled badly, this could really sour industrial relations, but it really shouldn't if sufficient effort is made to explain to the TUI FO's that they have not been disadvantaged. Sadly, history tends to not show that hese things are handled well, so fingers crossed eh?