So, yeah- as the system is now, it is a bit... broken. There are three options to make someone a private avatar, for a commission, for example, and none of them are exactly great.
  1. Log in using their account credentials to upload it directly to their account, so that the avatar can be set to private and thus can't be stolen if the person accidentally has cloning on. This is both against VRC ToS and generally unsafe.
  2. Make the avatar public, and have the person clone it from your account. This makes it so that the avatar can be taken and stolen by anyone should the person have cloning on. Would suck to have an avatar you paid to have made be stolen- and if you set the avatar to private, they can't use it anymore.
  3. Give them the actual unity package, model files, etc so that they have to upload their avatar /themselves/. This... is very inefficient, one, because not everyone has the Unity knowledge and skill to be able to do this themselves, and two... sometimes people make avatars from base models that are not allowed to be distributed. For example, Pikapetey's shiba model- you can take commissions on it, but you are not allowed to distribute the actual files, because it is a paid model and if you want the model, you need to pay Petey himself. Commissioners are not allowed to hand out files as per his terms.
This leaves only one single option that doesn't go against any ToS of either VRC or a model creator- making someone's private, paid for commissioned avatar, set to public, and making them clone it from you for other people to potentially steal.
Basically- there needs to be a way to transfer a private avatar to a specific, individual user for use WITHOUT having to use any of the above mentioned options. There needs to be a way to send an avatar to someone through VRC itself, and the avatar still remains /private/ and uncloneable by anyone except the person it is "given" to. This would allow people to actually efficiently commission PRIVATE avatars from people, without having to compile and upload themselves.