On July 26th my family of 3 and myself few out of LAX-SJO. I have a companion pass for my wife. My wife had Pre-Check on her pass, but non of ours did. When checking into our flight I pointed that out to the SWA rep checking us in. She said that should would try to add out KTN. Sure enough our new boarding passes printed out with Pre-Check on all of them. We walk up stairs and jump in the Pre-check lane. To my surprise after scanning my boarding pass by the TSA, agent tells me that I don't have pre-check and crosses it off my pass. Tells me I need to go on the normal lane. Scans my wife's pass and she's good to go. Then scans our kids passes and guess what passes shows pre-check, but tells us kids don't have pre-check. Needless to say it looks like SWA isn't ready for pre-check for international flights.
On a side note when coming back from our trip. Daughter pass had Pre-Check on it. There was 9 of us. 8 of the 9 are enrolled in either Nexus, GE or Pre-check.