davido didn't say that: "This works but is NOT recommended, and can be unsafe", and at least to me it's obvious that this refers to what you said
Using string eval on a proper hex string constant can not be unsafe. While warning aubout string eval composed of user input or some such is appropriate, it is not for this construct. Warnings should be correct. Saying to a girl "if you kiss that boy you'll get pregnant!" is, albeit often turning out true in the long run, incorrect and misleading. Hence my comment.
perl -le'print map{pack c,($-++?1:13)+ord}split//,ESEL'