Read on their own, I'd be inclined to agree - neither the 4th or the 5th on their own appear to prevent this. However, taken together, I'm not so sure. Clearly a person can be searched under the 4th, and the discovered evidence used. However, when the accused has to take a more active role (Face ID/Touch ID/password), that would seem to go towards being a witness against yourself. As such, any search under the 4th would go towards being an unreasonable search, warrant notwithstanding, as it is predicated on a potential breach of the 5th.

It's a bit of a stretch, but I don't think it's _wholly_ without merit.