Mike is correct about the getting 5 diffrent answers from 5 different Feds. It just like duty regualtions/ whatever that particular POI says is what you go with at that particular airline.
The one that really makes me laugh are the guys that have an MEI sit in the back seat- the pic under the hoodin the left seat and the the safety pilot in the right seat and then they all log pic/dual given. I totally disagree with that one but I hear there are flight schools out there that do it all the time.

 

I too agree it's hard to get consistent answers from the typical inspector.

Here is a link to a case in 1993 that is relevant. There was more going on here than just violation of part 61.51. These guys were both CFI's sharing time in an Apache. I think they were suspended for 90 days.

http://www.ntsb.gov/alj/alj/O_n_O/do...ation/4008.PDF

I will quote from the brief:

"The falsification charges resulted from the examination of both respondents' logbooks by FAA aviation inspector Donald Bennett during the investigation of an accident that occurred on 10 April 1992 involving respondents' Piper Apache aircraft. The inspector testified that the two logbooks were mirror-images of each other for over 200 flights. Both respondents were listed as pilot-in-command (PIC) for these flights and it was unclear when, whether, and what type of flight instruction was given."

You can log what ever you like. Just don't have an accident or incident or get ramped.