autovacuum vs. createdb

I'm noticing a problem where autovacuum touching template1 when createdb 
is run is making createdb fail. That's easy to work around when doing 
things by hand (just run it again), but when running createdb with a 
script, it's not so clear to me how to keep things working all the time.

One thought I had was having my script insert rows into pg_autovacuum 
temporarily (I assume in template1) but I'm not sure what tables I need to 
tell the autovacuum daemon to keep away from. Is that a reasonable idea, 
or is there a better one?