I agree. I've got at least a thousand infant baptisms (a.k.a. "christenings") , only a few adult baptisms and no conditional baptisms in my database. I actually know of only one person who was conditionally baptized as an adult.
One thing to keep in mind is that an adult baptism (conditional or unconditional) is normally of limited genealogical value. Something like being found on a list of voters. It normally does not indicate age, place of birth, parentage, etc. , unless it does. I'd record it using the adult baptism fact. There may be a theological reason why someone may, or may not, be baptized twice but I know of no Roots Magic limitation on the number of baptisms one person can have. (A scene from The Importance of Being Earnest comes to mind. )