So, I want to create a cold storage bitcoin address to store incoming BTCs from donations and payments (I'm a freelance developer so I'm getting used being payed with BTC). Since this address has to be spread among lots of different people, I can't change it so frequently, it's like my gpg public key, it would be a pain to change this address.

This means that I need a way to spend the BTCs stored on my paper wallet in a safe but fast way. The most obvious solution is using the Blockchain.info app, scanning the private key when required (I do not care about privacy in that case, I know I can be traced and such, but I'm ok that change goes back to the same paper wallet).

My question is, how much should I be worried about my private key being compromised by scanning it with my phone? Are there any known reports about this happening? Are there same safe ROMs that could prevent this?

If this is a serious concern, how can I spend the BTCs on my paper wallet in a same way whitout changing the public address everytime?