Erm, if you're going off some max psi limit you've set then check warm; otherwise tire psi is checked cold.
I check mine warm because I would like them to be running at 50 PSI regardless of outside temperature, and it's just easier to actually see where they are running than to play temperature guess work, but that's just me.
I had a normally-pressurized Dunlop SP20 fail on me once. 1000 miles on my new '97 Civic DX, 70 on the Interstate, and Ka-Blooey! Had to regain control of the car and pull over.
The tire completely separated into 2 pieces: 3/4 of the tread portion, and 1/4 of the sidewall in a completely even separation. No previous damage, no warning. I investigated it and it looked like a weak manufacturing process where the sidewall met the tread. No warranty coverage - Dunlop Corp. lawyers calling instead of customer service. It happened on the July 4th weekend, so getting to work, my spare wore-out and I had to buy another tire out-of-pocket when the tire-shop opened, and bought salvage tire/rim for a full-sized spare.
I vowed never to buy Dunlop again, and haven't since.
I sent the tire to them for analysis and never heard back (despite my several calls and threats to report to the BBB, Attorney Genl., etc.) Pics are documented.
LSS - the tire failed from within: bubbled and weakened at a seam. Water can do it, striking a hard surface/object can, overpressurization. But I've seen many name brand, normal-pressure tires bust belts prematurely as well. It's a crap shoot.
Wow.. that is pretty crazy. It is also enough to keep me from messing with my pressures at all. I am not even sure WHAT the brand of my tires is. I can only guess that they are the cheapest money can buy. A $4000 (new) car has to cut corners somewhere... or rather everywhere in the case of my car.
This is one of those things where you really do get what you pay for most of the time. The speed rating of the tire is going to tell you the most about it's overall durability.
That doesn't mean that one needs so called 'high performance' tires, but given what appear to be similar tires in every other respect, the tire with the higher speed rating is probably going to hold up to other abuses better. The cheapest brand at the store is priced that way for a reason!