I was about to draw a parallel with a local checker who won't handle shellfish. I believe her reason is an allergy rather than religion.
Anyway, you observation make more sense and is certainly a better parallel.
Being non religious, I have to ask myself would either one (the Muslim or you theoretical Christian position,) bother me. Answer; nope, as long as there was backup close by to complete my transaction.
Oops; you = your. (twice)
Since they also believe dogs are unclean, I wonder if she can scan dog food?
susie