I spoke to someone about this, the PA is suppose to send the passport to "VFS global". For example, there's only one VFS global office in Venezuela, which is in Caracas. Then after, I think they send it to Embassy of Canada, Mexico. Someone can correct me if I'm wrong on this info.
My wife lives in Margarita Island. I told my wife this before and she was so against using the courier to send from an Island to the office. What if it gets lost. The person I spoke to apparently dropped off her passport in person by going to Caracas and had to pick it up at the courier's office after.