always_direct & never_direct

I run squid-2.2.DEVEL3 with two parent proxies.

Squid configured to always directly forward requests for local servers:
acl localnet dst 172.16.0.0/255.255.0.0
always_direct allow localnet
never_direct allow all
prefer_direct on

But squid sometimes try to query parent proxies.
How can I completely disable this query?

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