Island Air... Used to fly little light airplanes loooong time ago. I often rented a Seneca and took friends with me. I was PIC I did let the other guys fly as we did share some of the expences. Anyways what they put in their logbooks was nobody elses business but theirs. They could have logged all as P1 and I could have not cared less. And would Airline give a toss if the fellow was alone in the airplane or not... As long as he performs on the simride. DUH
Before we get this emerging ( Not again ) JAR / FAR pissing contest to full swing I want to point out that Europe has a lot to learn from all that " nonsense " " Yanks " do. General aviation is in a lot better shape there than it is here in Europe. . .I fly on a FAA licence and validations. I have had lots of grief while trying to get work with it in Europe ( Nowhere else though ). Luckily I fall into the ECAC category. No problems since.
If you feel that 100 hours of multi in your logbook will enhance your employment prospects go for it.