This is funny because Im in a huge hurry to hit the road. I will add the descriptions tonight when I get to Seattle (I have an 8-9 hour drive). This is how you can fix your tripod leg if you ever pull it out of the assembly. If you dont know how to do, its a nightmare (typically people give up). If you know how it goes back together its pretty easy.
First of all- if you use a tripod as much as I do, this is going to eventually happen. The reason it happens is the lock snaps double as assembly fittings, so if the top screw (the one not attached to a clamp) ever gets loose, you will end up pulling a leg right out of your tripod. These are very cleverly made (if thats a word). You will see that each leg length has two holes near the top and there are 2 plastic half sleeves (in my hand) that have circular nubs that fit PERFECTLY into them. The sleeves usually come flying out the first time this happens to you. (dont lose them because you wont be able to fix it if you do). First put the locking mechanism back on, with the snap on the bottom (see below). Next, line up the circular nubs on the inside of the sleeves with the holes on the leg length so a the lip of the sleeve fits over the very top of the leg length. (See Red Arrow)There is a very small gap (about 1/8th of an inch) between each sleeve, these fit into grooves on the inside of the leg assembly. Make sure you line them up, otherwise you wont be able to fit it back in. Gentle push the sleeves back into the tripod, the tight space will hold the sleeves against the internal leg. Slide the snap all the way back up flush against the thicker leg and then tighten it so it doesnt come off. (on the picture below, the bigger leg is on the bottom)
In terms of prevention, you should also just check these to make sure they are tight and it wont happen in the first place. 🙂