This is something we've recently fixed; it will be included in the
next release (due out in a few days):
https://github.com/puppetlabs/puppetdb/pull/260
Our terminus code was always down-casing tags on resources, making
them better conform to the semantics of the Puppet Language:
http://docs.puppetlabs.com/puppet/2.7/reference/lang_reserved.html#tags
With the above fix, PuppetDB will now validate that all resource tags
match the rules indicated in the language reference, and queries
against tags are now case-insensitive.
It's worth noting that while you can query tags in a case-insensitive
way, matching resources will have "tag" parameter values that are
downcased (as that's how puppet sends us the catalog in the first
place).
deepak
--
Deepak Giridharagopal / Puppet Labs