Mashup Etiquette Question

Here's a question about Mashups:

How far can you go to make one song fit with another?

I was listening to a mashup show on my local terrestrial radio establishment; it took me more than a few moments to realize that one of the songs in the mashup was The Knack's My Sharona, only slowed down considerably -- it was practically a dirge.

The other song was some Franz Ferdinand song I don't know very well.

Apparently it's Do You Want My Sharona, by DJ Zebra.

It just seems like a breach of etiquette.