I'm probably one of the few who insist on doing a dead lift test on all my rods. I'm also very careful when doing it. I lift the weights very slowly off the the ground until they are just an inch off the ground. I start light and add weights as I go. I do this so I can know how much pressure the rod will take in fishing conditions. It's one true way to verify the action of the rod. I've found some rods to be rated wrong and the actions (slow, fast, parabolic,etc)
not to be as specified.
The rod will start talking to you when it is getting stressed. That's when you stop. I've never broken a rod doing a rod test. I have however broken a number of rods on fish. This usually happens to me when I've hooked a fish that was bigger than area normally holds. I get frustrated when I can't pour on the pressure. If a larger fish is caught on a lighter rod I tend to stress it more than it's design. If this happens, I try my best to use the reels drag and point the tip towards the fish. But, when the fish gets near the boat, a sudden mistake of using the rod to lift the fish will result in a broken rod.
If you can actually pull on the rod before buying, then that is a great plus. Since I live in a bass tackle town, I don't have that option. I have to buy on line and assume the rating is close to what I think I am buying. Normally it's a fairly good rating. Sometimes not.
If you want to dead lift heavy rated rods, make sure you don't high stick. It's better to stand on concrete steps that are at least three feet above ground level. That way you won't high stick the rod to bring the weights off the ground. As we all know, high sticking is the number one reason for rod snapping.
High sticking gives a false impression of placing more pressure on fish. Like MrBill states, high sticking should be avoided. High sticking simply progressively bends the weak part of a rod. The rod then breaks. The proper trick is to load the backbone of the rod. Few people know how to do this and I am convinced it is the real reason why "fishing the rail" works so well. The rail forces the rod to progressively load deeper into the blank. When fishing the rail, the rod is not usually bent more than 90 degrees.