We are about to sell our software product to a big company. For technical reasons, the product will have to be copied in its entirety to the client's computers, including at least some of the source code in plain text. Of course, the client will have to sign an agreement that prevents him from sharing, re-selling, reverse-engineering, or otherwise abusing the product.
I'm pretty sure a big company wouldn't bother taking a risk and "stealing" our product, because they'll have to update and maintain the product themselves (which is more costly than paying for it), and if they try selling it, they'd get a lawsuit and reputation damage (for starters). But our CEO is afraid that wouldn't stop them, so he wants some kind of "bulletproof" technological protection for the product, which I think is impossible under the circumstances.
My question is - has anyone encountered or heard of a case where a big company buys a startup's product and then steals it or otherwise violates the EULA?
P.S. While we're at it, can you think of another way of protecting the product from being abused like that (unfortunately, web-based application is out of the question for security reasons)?