Does a soaking tub require a reinforced floor?

We are redoing a house we just bought, and I really like the idea of having a soaking/soaker tub. I already picked out one by Kohler and am just waiting to order it. However, our contractor told my husband this week that soaking tubs need a reinforced floor. Suddenly I'm not able to have my soaking tub, or have to find a different kind. Is this true?