Read-only applications?

I just read "Safe Portable App-ing", and the rules there are so cruel that I don't believe I can follow it strictly.

I appreciate your assertion that "Whenever you plug your portable drive into an unknown computer, you should assume that it may now be infected with a virus", but I cannot accept that I need to virus scanning my USB stick and keep those backups all the time.

So, how about allowing the Portable Apps to be run in a read-only mode? I mean, if you do not trust the host computer you'll be using, you can turn on the read-only switch of your USB stick (I know some USB sticks have it) and run all applications in a read-only mode. You may not be able to save configurations, but at least all the apps run and you needn't care about the virus issue.

Well, Thunderbird will not work normal. Some document editors will not be able to save documents back to the USB stick (you can still use Firefox to mail the document to you). But, security is very important, and viruses are scary.