Bug in UTF8-Validation Code?

Hi,

I've a problem with a database, I can dump the database to a file, but 
restoration fails, happens with 8.1.4.

Steps to reproduce:
create database testdb with encoding='UTF8';
\c testdb
create table test(x text);
insert into test values ('\244'); ==> Is akzepted, even if not UTF8.

pg_dump testdb -f testdb.dump -Fc
pg_restore -f testdb.dump -d testdb => fails with an error: 
ERROR:  invalid byte sequence for encoding "UTF8": 0xa4

The problem itself comes from a CSV file, which is imported with \copy without 
proper quoting (so I have to fix this anyway), but I still think this is an 
error, making restoration very complicated in such cases...

Or am I doing something completly wrong here?

Best regards,
Mario Weilguni