Aww geez, you've got to be kidding me. We just went thru this.
Your Tahoe isn't big enough to flat tow a YJ. Yes the YJ is within the Tahoe's rated towing capacity but that capacity is based on a trailer adding weight to the the rear of the tow vehicle, its also assuming that anything over 3500# has its own brakes. Using a tow bar does neither of these things. The law for tow bars is that the tow vehicle should be twice the weight of the vehicle being towed.
Do people do it, yes, is it right or legal, no. I would say if you wanted one for an emergency recovery then sure buy one and have it ready but I wouldn't make it a regular procedure.
Look into a trailer or tow dolly.
Read here for the discussion we had on this last week:
http://forum.calgaryjeep.com/index.php?topic=14844.0