When you have just been issued with a fresh CPL/MEIR (frozen ATPL), are up to your neck in debt and not in speaking terms with your bank manager, and desperate for that first airline job, one of the most important things you have left is your
dignity. To advertise that you are willing to work for free is to do away with even that. Nobody should ever get on their knees to get a flying job - or any job for that matter. Full stop.
In my book, working for free can only be one of three things:
1/ Internship
2/ Charity work
3/ Slavery
Take your pick!
Cheers