I am developing a product using magnets. Do I have to put a safety warning on it about pacemakers/electronics?
While we love answering technical questions about magnets, this one sounds more like a legal question. We're definitely not qualified to provide legal advice.
Again, we are not medical professionals, so we cannot provide firm details on pacemaker issues. As for safety and electronics, it really depends on the application of your product, the size of the magnet(s), how the magnet is used, and where the magnet is located within the product. We recommend providing any warnings that you think may be an issue.