Ignored PostgreSQL SET command

I have a line in a PHP script that looks like this:
$set=pg_exec($dbconn, "SET DATESTYLE TO 'European'"); //Set date format

Since my ISP updated their server, this appears to be ignored as pgsql
always returns dates in ISO format.

1. What is the default format of dates returned that I can ALWAYS rely on?

2. Why is the command ignored?

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Patrick Dunford, Christchurch, NZ - http://pdunford.godzone.net.nz/
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the LORD.   -- Proverbs 21:30
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