Under US patent law, if a company releases a product or technology based on a patent which they do not have the rights to, can the end-user / consumer of this product or technology be held liable by the patent owner?
Yes. A patent gives its owner the right to try to stop anyone from making, selling, offering for sale, importing or using the patented invention. In fact a method-of-use claim is not infringed by the maker or seller but only by the end-user when it is put into use. In practice there is usually no money in going after end user consumers. However, there was a very noted case where a patent owner was abusively getting money from small companies who had bought a fax machine that could scan and turn the scan into an email. (Patent 7,986,426 and others) Also, if the patent only has claims on a method of use, the patent owner can sue the manufacturer for contributory infringement but only if it also establishes that at least one end-user committed actual direct infringement.