(b) Operate an aircraft that is equipped with an anticollision light system, unless it has lighted anticollision lights. However, the anticollision lights need not be lighted when the pilot-in-command determines that, because of operating conditions, it would be in the interest of safety to turn the lights off.
The chief counsel has commented on this in the letter to Murphy last year:
http://www.faa.gov/about/office_org.../interpretations/data/interps/2011/Murphy.pdf
She stated that for an aircraft with beacon and strobes, both have to be on if one is on, unless the PIC determines that they dont........
(really a non-answer, can't believe Ms Mc Pherson actually draws a salary for the non-work she does).
Still leaves me scratching my head what to do with a 'strobes only' plane.
I guess I can cruise around the non-movement area with the dim 5W positiion lights only. Now it comes down to weighing the risk of maybe temporarily reducing somebody elses night vision vs. the risk of permanently chopping someone who rides his golf cart on the ramp to little pieces.