"Nan McEntire" get numified to NaN on some systems, and the NaN check apparently causes <=> to return undef. 

$ perl -MDevel::Peek -e'Dump(0 <=> "Nan McEntire")'
SV = NULL(0x0) at 0x503848
  REFCNT = 2147483621
  FLAGS = (PADBUSY,PADTMP,READONLY)

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In reply to Re: Dangerous Names by ikegami
in thread Dangerous Names by samtregar

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