The MOST likely reason merchants were willing to risk their lives to charge more than the legal price is:
Merchants could not stay in business if they didn't raise prices.
This option suggests that the economic pressures and the need to maintain profitability in a competitive market could drive merchants to violate the law, even at the risk of severe punishment. The context of the speech indicates that the potential earnings from violating the price control were significant enough to outweigh the risks involved.