I have a 2011 with 5 inch lift 35 inch tires. I removed front and rear sway bars. I really enjoy getting off road with my overlander tahoe.
Upside:
On and off road the suspension feels great much softer absorbing bumps that would jar you to the bone before. It greatly improves traction off road because the wheels can track the ground more independently thus improving traction. When the suspension is able to move like this the ride over rough terrain becomes much smoother and the cab tends to stay more level. It laughs at most speed bumps.
We lifted one wheel with a fork lift a foot off the ground all four wheels stayed firmly in contact with the ground and the cab actually stayed more level than it did with the sway bars hooked up.
Conversely with sway bars on the rear wheel was lifted off the ground and 4 wheel drive became 3 and the opposite front suspension was collapsing limiting the available suspension travel and increasing the spring rate this would result in a much harsher impact if you hit a bump. Plus because the opposite suspension was being compressed by the sway bar it was causing the body to lean over much farther.
How much does it sway?
On the initial turn you will feel it lean out much quicker than normal and it feels like a lot more than what it really is doing. My first reaction was oh crap... But, after driving it and taking that initial emotion out of the equation I realized it was only moving that little bit then it became solid and felt about the same as before. I then took it out to preform some spirited turns and see if it could still corner like before. My entry and exit speeds into some of my favorite turns were the same I even added a few MPH faster in those turns and it still felt comfortable. My comfort in a turn may be much higher due to being a retired pro road racer.
My conclusion If you never take your tahoe off road don't bother taking them off. If you seldom if ever take it off road I wouldn't bother taking them off... If you like going around corners real fast well you should invest in a drop kit and stiffer sway bars.
If you hit a lot of bumpy pavement and go off road and don't mind a little sway and like the comfy soft feel like an old Cadillac then you might want to remove them. If you like running trails like the Rubicon and other serious off road areas you should certainly remove them. If you drive on wash board roads it will make your drive a lot better with them off.
What is the real chance of a roll over with them off... Depending what lift kits and other suspension modification you have your increased risk of a roll over could be between 2 to 5 %
I read somewhere in 95% of the roll over accidents it was caused by an impact with another vehicle or a solid object like a curb or poor driving decisions. The vehicle sway had nothing to do with the roll over in those cases it would have happened either way.
For me I will enjoy the softer ride on and off the road and depend on my driving skills to keep me safer on the street not a sway bar. In the end you just need to decide for yourself and do not depend on others emotions.