The written word is a powerful thing. All you have to do is look at the many wars that have been started over the centuries. Quite often, the forces on both sides of the battle line quote various snippets of their favorite religious books to show that their cause is righteous in the eyes of God. Sometimes they quote from the same book.
The administration of justice depends heavily on the written word, too. Police know that if they don't properly cross their t's and dot their i's, judges may well throw out the prosecution's case. The validity of contracts depends on the accuracy of the words used to draw them up. But even well crafted language is not enough to stave off legal action in some cases.
For example, just because a product happens to carry a tag with legal language that seeks to shield the manufacturer from possible liability if the product causes injury, that doesn't erase victims' rights. Texas consumers can seek compensation for damages, especially if the product was used in a way that most people would consider reasonable.
That is, if you buy a chain saw to clear brush on your property, follow the instructions on how to use it, and the chain flies off the blade and cuts into you, a manufacturer isn't likely to succeed in hiding behind a written disclaimer.
Now, if you happen to legally contract a local artisan to make a custom product for you and the contract includes a disclaimer against injury liability, a court might uphold the validity of the contract.
As you might gather from this, product liability claims can be complicated. If you believe you have a case, consulting with an experienced attorney should be the first step taken to ensure your rights are protected.
Source: FindLaw, "Are Product Liability Disclaimers Effective?" accessed Sept. 3, 2015