I can't imagine that anyone would actually think that having epinephrine and benadryl on hand would actually justify giving a contra-indicated treatment and re-reading the original post I do not think that this is how it was meant. It seems to me that she was considering possible outcomes, what the worst case scenario would be and how she would manage it if she elected to give the fentanyl.
I have not really read any of Epi-do's previous posts being new to this board, and I disagree with Epi's decision not to give the pain relief as there is no reason for the patient to have a reaction to fentanyl because they have had a reaction to morphine in the past (they may have a reaction to fentanyl, but this would be entirely coincidental)
However, that said it is obvious that this was done with the best interests of the patient in mind given the situation and understanding of the pharmacology, and she was clearly acting as an advocate for the patient and seeking to ensure no further harm came.
Further to this, the fact that she is asking opinions of other providers from all over the world suggests that she is a self-reflective practitioner seeking to improve her performance and this is exactly the type of person we need in EMS.