NEW ISSUE :Clarify usage of assertions with no behavioral requirements on the requeste

Re: NEW ISSUE: New Attribute keyword to identify 'local' policies #3721http://www.w3.org/Bugs/Public/show_bug.cgi?id=3789

Target : WS-Policy Framework and policy guidelines

Justification :

There's a class of policy assertions which have no behavioral requirements on the requester but can be still usefully processed by 
requesters which are aware
of what assertions mean.
For example : <oasis:Replicatable/>

An assertion like this one can be a useful source of information for requesters. Providers having expected properties like 
<oasis:Replicatable/> can be chosen/searched.
At the same time, given the fact assertions like <oasis:Replicatable/>
have no behavioral requirements on the provider it's important to ensure
policy-aware clients which have no knowledge of these assertions can proceed
consuming the service advertsing this assertion.

Currently the way to advertise such an assertion is to use a normal form with two policy alternatives(simple case), with only one 
alternative containing this assertion thus making it optional, or, in other words, giving a chance to requesters to ignore it.
Such normal form expression is equivalent to a compact form with the optional assertion marked with wsp:optional attribute with a 
value 'true'.

However, at the moment the primer recommends using wsp:optional when one needs to mark asssertions which identify optional 
capabilities/requirements with behavioral requirements on a requester should the requester wishes to use it.

Thus marking assertions like <oasis:Replicatable/> with wsp:optional is considered to be a wrong approach.

Proposal :

Clarify the text describing the optionality in the policy guidelines and in the Framework spec on how a policy author should use 
assertions like
<oasis:Replicatable/>.
It's important that assertions like these can be usefully interpreted by knowledgeble requesters and safely ignored by requesters 
unaware of them.