THere is no way that they would use yellow tags even if they were going to try something new. THere would just be too much confusion at the airport. And heaven knows, they don't need anything else to confuse them over there. So, we are just going to have to assume that the vendor made a mistake. I got duplicate tags a year ago...the correct ones had my right resort/flight times. The incorrect ones had the resort I was moving to, with my flight departure time on them. Go figure...they simply made a mistake.
If, sometime down the road, they do add SW, it will involve adding more people to the desks. But, it won't involve more luggage tags. The RAC desk uses regular airline type bag tags since they are acting as an airline agent, just off-site..hence the name RAC...remote airline checkin (or close to that).
Adding SW will have it's own set of issues...what happens to seats? If we get to check in up to 24 hrs ahead, will RAC then just take our luggage, tag it and send it on to the airport and we use the boarding passes we got the day before? Who knows. But, it will be interesting to watch it play out.