Erg... I spoke to soon about the -s switch not being honored on the shebang line... it's a little bit odder than that. It is honored if the script is invoked by the shebang, but not if it is invoked by a direct call to the interpretter (and, thus, that the shebang line just gets parsed by the interpretter):

[me@host]$ cat t2.pl
#!/usr/bin/perl -s
use strict;
use vars qw($a $b);

print "a: $a\n";
print "b: $b\n";
[me@host]$ perl t2.pl -a
a: 
b: 
[me@host]$ ./t2.pl -a
a: 1
b: 
[me@host]$
[download]

This is really weird, as most switches should not behave differently if the script is invoked by the shebang rather than by calling the interpretter explicitly... Really frickin' odd.