If Sudafed returns a false positive because of pseudoephidrine, then there is going to be lots and lots of trouble if the testing can't distinguish between it and other drugs.
Occasional SCUBA divers like me always keep it handy because a head cold or sinus irritation can ruin a $5000 diving holiday without it. I'm sure that there would be a lot of pilots who would keep it handy as well for approximately similar reasons.