Puppet users - May 2014 - Facts can override variables set by puppet master

Hi,

The puppet master sets several global variables, including $environment,
$serverip, etc
(http://docs.puppetlabs.com/puppet/latest/reference/lang_facts_and_builtin_vars.html).
However, looks like client facts with the same names can mask out these
variables. How can one determine reliably the current environment inside
a manifest/module?

I'd consider this an issue, for example, because with puppet 3+ the
environment set by ENC is authoritative and may differ from the
client-set environment and/or client fact with name 'environment'.

Thanks!

BR,
Boyan