It is just like if you had a heart condition and your doc was going out of town some other doctor would be covering for him/her and would have full access to your med records. Your T is just leaving someone to cover incase any of T's patients need something. The more info the fill in T has the better they can help the patients.

I don't really see it as an invasion of privacy or anything. It seems a caring thing to do to me. It shows T cares and doesn't just say "i'm gonna be gone, take care of yourself".

If you have a problem with it you should talk to your T about it. If you have someone to go to while T is away and don't need the 'fill in' then tell T not to worry. But if someone needs the fill in T then that T will need all that info to be of any help at all.