Anyone can create tables!

Ive been using PostgreSQL 7.0.3 since about the time it came out. Im
very happy with it. Cheers! But im writting to ask about a problem ive
noticed. Any user with access to a database on my system that isnt the
owner still has the ability to create tables (and possibly functions,
views etc.) with no aparent limits. Is this a design flaw or a bug or
perhaps just something you guys havent got around to fixing yet?
Personally I think that a normal user should not be allowed to create
anything in a db he doesnt own. Anyways, i look forward to hearing back
about this as it is kinda putting my latest project on halt until I find

a way to stop this. Also, is there a plan of any kind of space/db/table
size
restrictions any time soon? Thanks