Steve, agree with you that they can always rationalize and minimize, as usual !
However, from what Wikipedia says, it seems that it is not really "have to have the symbol".
It states:
"While no agency is tasked solely with enforcing its use as a mark of certification, the Star of Life has traditionally been usedas a means of identification for medical personnel, equipment, and vehicles."
Check: http://en.wikipedia.org/wiki/Star_of_life
This seems to mean that it is not compulary and no agency is assigned to enforce it. They could have avoid it, but as usual, if it means $$$, then no problem with any symbol.
Here I am referring to the fact that they want to appear "social" to the comunity, because of the fact that they pay little or no local taxes, being a non-profit org.