Reg. Exp in address matching

Reading in Majordomo help (on the list's owner doc) found that using regexp 
was posible for some matchings, but when I tried to put a rule to let 
everybody in a domain post to a list, it didn't work, then i found reading 
the majordomo.pl file, on line 188 (in the definition of addr_match) the line 
that follows:
return($a1[0] eq $a2[0]);

so it doesn't let use regexp in address matching, I was thinking that colud 
be better to use:
return($a1[0] =~ /^$a2[0]$/);

Have made some test, and it seems to work fine, but I would like to know if 
there is some problem in changing this (like security fouls or mal function 
in some rare cases)
These test were made in majordomo-1.94.5.
Thank you for reading this lines, and please forgive my lousy english but is 
not my mother tongue.
greetings,
          Luis Michelena
          Postmaster
          Facultad de Medicina
          Universidad de la Republica
          Uruguay