AL3,
I would suggest Part 135 is pretty restrictive.....but enforcement of 135 in the EMS world is pretty well non-existent. Neither the operators or the FAA really do a decent job of living to the rule.
The problem is the conflict between complying with the rule....and getting the job done.
Simple case in point.....Night VFR surface light reference requirements.
There's lots of very dark places in the country and how many of us ignore the requirement to have that bit of help from the lighted objects on the ground and just cruise on over those dark places knowing there will be lights at our destination? Everyone of us are illegal to do so but we do it (I have to use past tense for me as I am now happily and safely retired.).
How many times do you break the rules before the odds catch up with you and turn you into a statistic?