nowhere near paranoid enough ...

 .. but foolish in the extreme, to boot

«My nine year old daughter has a friend who passes along lots of chain stuff, games to play, etc, with extollations [sic] to send to everyone on your list. I opened a couple, so the best I could do was explain what I thought was going on to her little ladyship and teach her not to pass things on. Am I being paranoid?»

[An obvious internet naif[1]]

For any- and everyone: By definition, there are new viruses being created all the time. Ergo, also by definition, not all viruses will be detected, no matter how good you may think your anti-virus/net-nanny set up may be.

The obvious conclusion is that anyone opening a couple puts their PC into grave danger.

Our rule is open nothing, not even from friends, without proper checking (I have my own ways), and, most importantly open nothing, ever from unknowns. An unknown, in this case, includes any child/teenager.

The behaviour of the naif is termed unsafe internet, and is equally as dangerous as unsafe sex, PC's or you can die from it.

-=*end*=-

Ref(s):

[1] naif
adjective naive or ingenuous.
noun a naive or ingenuous person.
ORIGIN from French naïf. [Oxford Pop-up]