Thanks very much for your thoughts and opinions everyone. Good discussion.
For the record I think I agree with majority - if insured go for it. They need a machine moving, you need the experience - a mutual back rubbing session! So long as you keep an eye on the bigger picture I think everyone stands to gain (except perhaps the pilot who might have been paid to move the helicopter).
All in all to turn down hours at such a nascent point in your career is probably not going to help you get to where you want to be. Which is your bigger concern - not work for free cos you wouldn't like to have work taken from you if you were an experienced pilot or really struggling for work cos you have no hours/came across as arrogant?
I think this situation highlights how working for free can be a bit of a grey area and to simply say never work for free (which let's face it is what would be happening in this situation) is not an easy thing to do when starting out. But I suppose advertising your services for free, as has been seen, is a slightly different matter.
Cheers again.