Not really sure it's really a moral issue other than in dealing with such things both employee and employer need to act with integrity.

I always cringe when I see posts on this forum (I do not mean the above question) that advocate "grey" or even quite black behaviours.

When I used to work as an employee and later within my senior management roles, my principle was always of full transparency. In many organisations there are specific policies that set out the rules. Where there are none or it is unclear, it is sensible to agree in writing with the organisation on this sort thing and make it all clear and transparent, then stick to what is agreed.

It's no good to complain about having to fly, or having to do this outside normal business hours when this is part of the stated job, i.e. part of why you are employed and given a salary in the first place! It's a job, not charity. If you don't like it, then find another one.

In the end, it's all about a mix of duties and benefits that works for both parties. As a director, I was quite happy for staff to enjoy the perks of their miles but I made sure this was formally acknowledged and recorded.

I've never fired someone for making an honest mistake (even costly ones) as we are all human, but I certainly have fired people without further ado when they show lack of integrity (and no, not being found out is not the same as behaving with integrity).

Don't give them any ideas, next thing they'll ask for holidays!