• Allow lookups of players who are offline.
• Add permission altdetector.exempt to exempt the player from processing by the plugin.

A note about offline player lookups: When you issue /alt <player> for a player who is not currently on the server, the plugin will find the player's most recent IP address and do a lookup based on that. If the player has used multiple IP addresses recently, or if the alt has been shared between multiple users, this may show inconsistent results. For example, A may be shown an alt of B, but B is not shown as an alt of A. This is not a bug, but is due to multiple IP addresses being used for one player.

Thanks to JackTheBoy8 for the suggestions.