I think the answer is no. Well normal visitors around the web doesn't really care about your google ads. The only one that is aware of those ads are the webmasters like us.
Perhaps by using DFP ? http://www.google.com/dfp/info/sb/index.html But what do you have to hide? Your other sites? Who cares? You're afraid of competitors copying your ideas.. Well it's weak, you shouldn't waste any second about that..
why you got "enemies"? What are you affraid of anyway? with them seeing your account. I wouldn't sweat it myself.
When we do b online business - Not all professional people you got .. so we need to take the security of our business.
There's no need to hide publisher ID. Big sites like CNN, BBC, CNBC, Bloomberg, etc. have their publisher ID visible on their site's source code.
They are all big sites thats why they are no worry about this issue .. because google easily heard their voice .. who gonna heard our voice.. My personal experience said all. They have much expert webmaster team so they can easily solve any issue which they face.. for a single webmaster or new webmaster not easy to do..
1. Build a quality site. 2. Use your "allowed sites" settings in adsense. and you will have nothing to worry about.