I see that line appear a lot in instrument reviews here on UG, and I'm wondering what it's all about. Are most people implying that they expect to throw around their instruments when playing live, but treat them nicely at home? I understand "Can I trust it not to die on me during a gig?", but "Withstand live playing" sounds like guitars are expected to be smashed around when playing live.
They just say that to put an emphasis on the instrument's durability.

They just worded it differently.
It just means, "Is it trustworthy enough that it won't die on you while you're playing?"
Peavey HP Signature EXP (SH4 JB/ SH2 Jazz)
Jackson DK2M
Fender MIM Stratocaster HSS
Fender MiM Telecaster

EVH 5150 III w/ EVH 2x12 cab
Peavey Vypyr Tube 60
Fender Blues Jr.

Boss ME-50; NS-2; RV-5; BF-3
MXR M101 Phase 90
No, it's just some guitars just disintegrate when they see a stage.

Must be nerves, poor things
My "Rig":

Fender American Telecaster
Boss OD-2
EHX Small Clone
I usually see that term used on pedals more than the actual guitars. And rightfully so. I would imagine during a massive solo when you decide to up the distortion, you run over and SMASH THE HELL out of that stompbox. Ive never gigged before, but I imagine it might be like that.

Also, look for a "Hendrix Proof" sticker. If the guitar has that, then you can burn it without damaging it.
Depending on the person, when playing live some of us tend to get a little more animated and move around alot more which in turn gives you alot more things to smash your guitar into and so on. More sweat and odds are good you will spill something on it atleast once.
Meaning that while a epiphone lp special is an ok guitar to play around in your bedroom, the construction and quality of the components is not good enough to withstand too much of the abuse it would see if you regularly played gigs with it.
pics of gear updated on profile 11/16/09
Hmm I've gigged with my epi loads, and have never spilled anything on it or smashed it into anything.... Must just be me :P
I am sure there are lots of people that have never smacked their guitar into anything or spilled anything on them. That does not mean that it doesn't happen though. Even bigger bands have these problems. The Guitarist from Uriah Heap died when something spilled on his amp and electrocuted him. during one of their first gigs, Pete Townsend from The Who went to raise his guitar in the air and ended up jamming it into the low ceiling of the bar and snapped the headstock off starting the infamous equipment trashing he is known for.
Hell, look on Ebay and see how many guitars are sold with " A Few Small Dings" in the ad.
There is nothing wrong with most Epi's I just used the crappy Special as an example and if you are gigging with one of those then you need to have your head checked.
pics of gear updated on profile 11/16/09