It depends..... the spring that the trigger lever pushes against is the biggest factor. But friction between moving surfaces is a big factor and the firing pin spring has an affect. Sadly, it takes more than just adjusting the three screws to get a lower poundage, safe, consistent trigger.
Opinions by Jay

What is the lightest you can go on a stock 700 trigger? If you adjust it too low, what happens? I ask, because I just bought a 700VS and have been playing with the trigger, but I'm not sure about the limits it has, and I don't want it to become dangerous, or unreliable. Thanks for the input.

Hey Jeff,
I generally set all of mine at 3 1/4# and call it good. I was having fun adjusting one lower and lower one day. At 2# it was fine. At 1 3/4# The firing pin would release when I went from "safe" to "fire", or just from closing the bolt with the safety in the "fire" position. If you want it much lower than 3# I would recommend having a gunsmith like George Vais in Boise work on it, or buy one of the aftermarket triggers. The Jewel triggers are incredible. You can get one in the ounce range for target work or one in the low pounds range for varmint shooting.
JCN

I apologize for being vague, I read several write ups on how to properly adjust the trigger, and by "playing with it" I meant that I had been experimenting with different pull weights. The question stemmed from all the articles telling you how to adjust it, and how low to go, and how to safely test it, however none of them explained what would happen if you went to light, beyond saying the gun could have an A.D. I was trying to get some clarification on whether adjusting it a certain way might damage the trigger and/or the gun, or pose other problems. I have the trigger to a point where I like it, and I have run all the safety checks that the articles listed, I just thought I'd try and get some more details on potential reprocussions with adjusting it too light.

Not trying to be an *sshole, but "playing" with a trigger without knowing how to safely adjust it is risky business. I know a guy who decided to lighten the trigger pull of his Rem 700 25-06 before a hunting trip. After he had it like he wanted it, he decided to check some handloads by chambering them. First round fired when he closed the bolt. Fortunately, his wife, sleeping in the next room, was only frightened out of her wits. The televison, sadly, was not so fortunate. He had reduced the sear engagement almost to zero.