Constraint names using 'user namespace'?

Just noticed this:

pjw=# create table pk1(f1 integer, constraint zzz primary key(f1));
NOTICE: CREATE TABLE/PRIMARY KEY will create implicit index 'zzz' for
table 'pk1'
CREATE
pjw=# create table zzz(f1 integer);
ERROR: Relation 'zzz' already exists

Is there a good reason why the automatically created items do not have a
'pg_' in front of their names?

----------------------------------------------------------------
Philip Warner | __---_____
Albatross Consulting Pty. Ltd. |----/ - \
(A.B.N. 75 008 659 498) | /(@) ______---_
Tel: (+61) 0500 83 82 81 | _________ \
Fax: (+61) 0500 83 82 82 | ___________ |
Http://www.rhyme.com.au | / \|
| --________--
PGP key available upon request, | /
and from pgp5.ai.mit.edu:11371 |/