YOU go girl!!
The poster should have read Appendix A of the CPT manual. It is very clear that it says the following:
Modifier 21 has been deleted. To report prolonged physician services, see 99354-99357)
To reiterate, just because you bill for a service, there is NO guarantee of payment.
It is always your responsibility to make sure your claim is 100% true, accurate, and complete (It says this on the back of the claim form, right next to the pyramid with the eye on top). Keeping on top of cpt code and modifier changes prevents claims denials.