You say "/i has no impact with the character class". Which in this case is true as the class is [A-Za-z] but is not generally true: 
perl -Mre=debug -e'/[a-z]/i'
Compiling REx "[a-z]"
Final program:
   1: ANYOF[A-Za-z][] (12)
  12: END (0)
stclass ANYOF[A-Za-z][] minlen 1 
Freeing REx: "[a-z]"

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In reply to Re^3: RegEx Help by Anonymous Monk
in thread RegEx Help by Brian268

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