Just one of the reasons it is a violation of most
"safety codes" to plug an
extension cord into an extension cord!
Typical!. Prevent something that can actually be quite useful because
it's possible for it to be dangerous if the devices (i.e. the extension
cables) are mis-constructed. Don't actually deal with the real problem,
namely getting extension cables made properly in the first place.
Incidentally, I never buy read-made extension cables, I always make my
own. It's the only way to be sure they're made properly. (Oh, and don't
get me started on moulded mains plugs. Suffice it to say I cut those off
and replace them with proper plugs as soon as I get the device!).
-tony