The following statement is incorrect:
"ExMerge may still be useful for some scenarios, because there are a number of items that the Recover Mailbox Data feature does not address:
Does not allow for merging or copying rules and permissions. This means that rules and permissions in the recovery storage group database will potentially be lost after the merge is completed. This will not affect users who swap the dial tone, or blank, database into the recovery storage group prior to merge."
When you recover mailbox data from a dial-tone database, you can run into the scenario discussed in KB article 923117, where blank permissions are written to the production database, causing a loss of permissions. The steps in KB article 923117 should be followed when client permissions need to be retained.