My sister flew WN twice this week, DAL-HOU, and HOU-AUS, and both times she couldn't do online check-in, and actually had to go through secondary security check at the airports.

Her tickets were purchased seperately, the HOU-AUS with 14-day advance, and DAL-HOU with about 7 day. Single passenger. I would think that's pretty normal for people to fly a lot of one-way intra-Texas flights, as they're basically just bus rides for us. The only thing that's slightly extraordinary is that her residence is in PA, not TX.

Still, these are her first two times trying to do online check-in, and so far her success rate is 0%. Any idea why? [And she's not on FAA's "no-fly" list, as her other recent flights on US, CO and UA have zero problem!]