Yes, caps are sort of more binding. The Uniform Commercial Code (UCC), a set of laws about contracts and commerce that has been adopted by all the states in order to normalize comemrcial law in the US, requires that certain parts of a contract be "conspicuous," because they go contrary to the legal "default settings."

For example, competently written contracts will usually have all caps or large font for the disclaimer of the two implied warranties (merchantability and fitness for a particular purpose), because wherever the UCC is the law of the land, a seller implicitly warrants those two qualities in what he sells. He must conspicuously disclaim them in the contract.

This is why, e.g., in the brief form of the GPL included with programs it reads:

"This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details."

Specifically, the two implied warranties are disclaimed in caps. See http://www.law.cornell.edu/ucc/2/2-316.html for more