rp3 reported a fatal crash (core dump) when I tried to delete the only registered modem on ttyS0. (When running rp3 for the first time, the modem which is really on ttyS1 was misdetected on ttyS0, probably because it was in use at the time.). The only way I was able to get rid of the ttyS0 modem entry was to delet /etc/wvdial.conf
As far as "misdection" goes, you are correct that it cannot detect a modem that is currently in use. There's not much of a way around that, unfortunately. It just didn't look at that device that was in use and took the next best. If there really was not a modem on that device, it should have told you that it couldn't automatically detect a modem, and was offering you its best guess... The fatal crash, I think, is fixed in our current development sources. We're trying to track down a different bug before doing a new release.
We are releasing rp3-1.0.1-1 as an errata update to Red Hat Linux 6.1. Please see if it fixes this bug for you. We expect it to do so, but it's always possible that we fixed a different bug from the one you are experiencing.
We'll assume that rp3-1.0.1 fixes this problem. Please reopen this bug report if you find otherwise. Thanks!