Here's the problem...
If you state 2 ohm stability, someone will want load the amplifier HARD at two ohms and wonder what is wrong with it when it hits the wall and decides to protect itself. He will then go on every forum in the world and and call it a P.O.S for doing so. How DARE it turn of when it is delivering square waves!!! The nerve!!!
Also, very few speakers actually stay ABOVE their rated impedance at all frequencies. Typically they dip BELOW their rated impedance somewhere, and many times that that can be up to half their nominal rated impedance (and of course, life being what it is, this will occur at a frequency where the speaker needs LOT's of power). So, your 4 ohm load may look like a 2 ohm load; your 2 ohm load may look like a 1 ohm load... you get the idea.
The amp will look at the volt/amp product on the output stage and say, enough is enough and inhibit. Now, this cowboy will will be upset and let the world know it! Typically, the worse judgment a person uses is directly correlated to how loud they scream when things go wrong... and it is never their fault!! It's that shi**y amp we sold them!! If you have a teenager at home, you've witnessed this logic many, many times.
Lonnie and I love to beat the crap out of our amps. It's kind of a hobby with us. We can load an XPR at two ohms, with a real speaker load, and play it like we stole it and never hit the protect. But we can hear clipping and we are sensitive to other signs of distress, so we will back off when it's clear that we're pushing our luck. And by the way, many times it is the SPEAKER that is screaming for help, not the amp!!! And if you want to see some weird loads, saturate the inductors in the crossover of a typical hi-fi speaker, or push the voice coil so hard it leaves the comfort of the magnetic gap; then things get really ugly!!
But, can we assume that all of our friends out in Emo-Land have our handsome looks, good judgment, steady hands, and common sense?? Maybe they've had a little too much Jack that night and throw caution to the wind... maybe they are trying to impress their buddies... or maybe they are trying to see how many blocks away from home they can still hear their stereo (BTW, I've done this!! MORE THAN ONCE!!!
)... who knows? But you get the idea.... things can, and do, get out of hand.
For you see, I was once that nightmare customer who could LITERALLY catch his speakers on FIRE!!! Not smoke, FIRE!!!!! And then complain when they weren't covered under warranty for the SECOND time!! I was the IDIOT who routinely put aluminum foil on the fuses of my poor old Phase Linear 400 amplifier to save money because I blew them out so often!!! I used to load every speaker in my apartment (and my friends) to that amp just to watch the ceiling lights dim to the beat of the music!!! I used to listen to my stereo poolside from the open door of my apartment, THREE floors above, and at the OPPOSITE end of the building!!! Really!!!
I had absolutely NO common sense. I WAS the cowboy!!! I know this person well, for he was once ME!!!
This is why we state the specifications conservatively, as we KNOW you will push things. We have many customers just like me! We'd be disappointed in you if you didn't have a little fun! Go ahead a load it at 2 ohms, it'll probably sound great, and you're not going to break it. But don't *bleep* at us if the amp protects! It's talking to you, so please listen.
Go forth and sin no more. And be smarter then me.
Class dismissed.
Happy New Year!!
Big Dan
)... who knows? But you get the idea.... things can, and do, get out of hand. 
