What should stop is the nonsense that the payment was a "re-imbursement".    It's simply a token sum.

The jet had to fly anyway, so the incremental costs of an additional passenger is negligible, but agree that it's nonsense to say that this staffer "re-imbursed" the cost.    She only provided a minimal token sum that reflected an economy ticket.    Given that this was a private jet, with private terminal access, no lines, no hassle, no baggage checks, or security, she should have at least re-imbursed for a larger token sum.

Maybe the problem is the wording.