No permissions of any kind should be needed for this file simply because it's an attempt to restore default Skyrim settings. However if you make it more stable I'd love a mention when you post for revision for the simple reason that I can see what I may have done wrong.
File credits
This author has not credited anyone else in this file
Donation Points system
This mod is not opted-in to receive Donation Points
This is a very small mod made to restore the behaviour of Dawnguard Merchants modified by the Unofficial Dawnguard Patch. The UDGP mod refers to this change as "Dawnguard members will not offer to sell things to the player if they have joined the Volkihar Vampires. (Bug #15136)". I disagree with this change as Pacify is meant to make friends of enemies & so they should offer the same services as if you were not a vampire. Also UDGP didn't fix the Dawnguard merchants completely... with UDGP if you pacify them they will actually still sell to you they just don't have access to their merchant chests when you access their store. Instead they sell some swords & cross bows only. Beyond this they will also still train you in skills which seems paradoxical in nature... "we won't sell you items but we'll make you a better killer". This mod achieves restoration of the original behaviour by modifying the form IDs in the faction section that UDGP modifies to change CITC - Condition Count from 1 to 0 for all the modified Dawnguard members. I hope this doesn't cause any conflicts or troubles however it's my very 1st attempt at making any changes to Skyrim myself instead of just using the Nexus Mod Manager to add mods. Load the ESP after any of the Unofficial Patch mods you may be using to ensure the settings work.