% steph@ape (/home/stephan/r) %
% perl -we '$@ = "customer stuff..."; eval { die "dont muck with $@!" }; print $@'
dont muck with ! at -e line 1.

% steph@ape (/home/stephan/r) %
% perl -we '$@ = "customer stuff..."; { local $@; eval { die "dont muck with $@!" }; } print $@'
customer stuff...