So here's my experience from the past few days. I've never had anything like this happen before and I've flown on more than one or two flights, airlines and tickets with multiple airlines on them. I book a ticket YEG-YYC-LHR-PRG and return. YEG-YYC is on WS (BA codeshare flight number) and the rest is on BA. The ticket is booked from ba.com. 24 hours before departure I hit BA's online checkin and find out I can't checkin yet because its' not 24 hours before departure of the first flight on their iron. Conveniently the error page tells me the WS PNR so I go over to westjet.com and use that PNR to try to online checkin for the first segment of the trip. The online checkin process starts grinding away and displays to me my name to select for checkin. I choose it and click next only to be presented with "an error has occurred <blah> <blah> <blah>". Nothing specific was in the error message. I try off and on for a couple hours always with the same result. I call WS support and am told by them that "IT says they have the system offline for a couple of hours. Try again after that"...which sound pretty suspicious. So I try again for a few hours with no success. 12 hours after checkin opened I still was getting the same message. I reached out via twitter and was told that I couldn't checkin because "there are partner airlines on your ticket." Okay....whatever....this is obviously a problem that *no* other airline has ever encounter or fixed...but whatever. I resign myself to standing in the queue at the airport to do my checkin. Meanwhile, my flights on BA have opened up and I've been able to checkin on those flights and get prime seat selection. Since they're the longer flights I'm a happy camper. Departure day comes and I get to the airport and there, miraculously, is no queue. I go right up to the checkin agent and start the process. He gets me sorted out for the first segment on WS and then starts to slow down. He asks some jumbled set of words that sort of mention "...your frequent flier..." so I tell him that I'm crediting to BA and using that number and that I've already successfully checked in on those flights and have printed boarding passes. He says "oh, that's good. You're good to go then" and sends me on my way. Flight to Calgary was uneventful (although I never realized how antiquated the IFE on the WS planes were). I get into the lounge, enjoy my wine and then head off to board. My section gets called and then it all goes to hell. When they scan my printed boarding pass the system flashes red and I'm told to go to the side. After some consternation and about 3 BA reps looking at the system I'm told that "we didn't expect you on the flight today". I double check my brain and sure enough it's the right day for my flight. I few minutes later I'm told "It looks like WestJet off loaded you from the flight so we're working to get you back on it". WTF Buttercup? So I was off loaded, my seats were given away and now BA was scrambling to see if they had space on a flight for me. Turns out there was one remaining seat on the plane and it happened to be in my booked class. By this time we were getting close to departure so the BA reps told me to check at LHR to make sure the return segments weren't messed up too. Luckily BA confirmed that there were no issues with the return but the agent there couldn't fathom how or why WS would offload me. I haven't flown WestJet in almost 7 years. I know the hillbillies and rednecks in my part of the world swear by them but I suspect that few of them do multi-airline trips. Is this kind of ****up normal by WS standards?