Should a gem set $KCODE in ruby 1.8 for others?

Hi,
I recently got a request to make my gem utf-8 friendly:

since my gem involves calculating string lengths. For ruby 1.8 I need
to use jcode’s jlength() to calculate this correctly but I’ll need to
set $KCODE in order to use it. Is it considered intrusive to set
$KCODE in a gem for others considering its global effect? If so, then
I’ll probably just copy jcode’s jlength() into my code.

Thanks,
Gabriel