Yeah "should be fine" is the key. I'm still skittish from being completely unable to check in Mrs. Milepig on LH earlier this week with a perfectly normal ticket. I checked in just fine, but nothing I tried would work for her. I finally had to call LH where it took someone 10 minutes to work some magic so I could check her in.

For me I just entered my UA FF number and last name and I was able to check in just fine. For her we tried FF number, we tried PNR, we tried the ticket number, nothing would work until I called.