Will I loose iPad application data when I switch Apple ID? I have borrowed iPad2 from a friend. It does have iOS5 currently installed.

I do want to install (with friend's permission) few free apps from App Store. However, even installing free app require entering password to my friend Apple ID. Since obviously friend does not want to share it, he allowed me to log out of his Apple ID and log in to my own. However I am afraid that switching accounts on iPad might result in loosing data like photos or application data.


Will switching Apple IDs on iPad cause any data loss? If so, will that data be restored automatically when friend log in back to his Apple ID?
Will I have access to apps installed with other Apple ID?
Will updating system from iOS5 to iOS7 cause any data loss?
Can I log in to multiple Apple IDs on one iPad? If so, will it cause any data loss?
I believe this depends on they way the App is set up. If an app backs up its data on iCloud then it will not be able to retrieve it as each Apple ID has separate iCloud storage space. On the other hand if the app uses its own server for syncing (and you use the same login details) I would imagine it will restore data appropriately. 
However purchases made with one Apple ID are not available to another Apple ID. I am not sure if Apple offer transferring purchases but I guess you could contact them to see it they could do so for you.

1) I don't think changing Apple ID will cause any data loss. I switch between two and never had any issues (I would however check with Apple)
2) Yes, but you might have to download them first if not already on the iPad.
3) This could happen as the apps will have to be updated and since iOS5 most apps have heavily changed both visually and the way they work with say iCloud.
4) As stated in (1) I don't believe you should loose any data but you can only have one Apple ID active at a time.

Make sure you take a full backup on your computer before making any big updates like moving to iOS7 from iOS5.