We've been seeing an increase in the number of Lync folks that have native Lync clients connected to a non-open environment. Largely these appear to be US government folks.
When we attempt to invite them to a meeting, their native client takes priority and attempts to connect but fails due to their non federated environment or firewall. We then have them back track and open up the web client.
While this is a workaround to get them connected, it would be nice if this was not a manual process as a considerable amount of meeting time has been wasted directing non-technical users to this work around.