I tell people to read through their whole warranty if that is a concern. Most warranties require professional cleaning every 12-18 months (with a reapplication of protectant each cleaning). If they haven’t been following this, their warranty is already voided so it doesn’t matter how their carpet is cleaned. That said, we can perform steam cleaning (via portable) if that is what is required, but it is not our preferred method. I further explain that most carpet warranties are a joke and many of the commercials show spills happening that actually would void the warranty in some cases. Give them all the facts, and then let them decide who to use and what method, but make sure it is an educated decision on their part.