I've had the experience. Not good, but I'll tell you. I called Mears before I left and they assured me that I was to notify my bus driver when he picked me up, and he would call Southwest. So I did tell him, and he just gave me a blank stare. When he got on the bus, I asked him if he was going to call and he just said "No". Then when we got to Terminal B, he just left me, told a CM there that I'd need a wheelchair, told me to sit in a certain spot and I waited...and waited....and Finally a kind gentleman stopped by and said "Are you STILL here?" He had nothing to do with wheelchairs, but he did take pity on me and pushed me all the way to the Southwest counter (By the way, this was a solo trip, so no 'party' to help). When I got home, I called Mears, asked them what the procedure was. The gentleman gave me the same line about "Tell your bus driver and he'll call", then I said "Well, now I'll tell you the reality" and told him what had happened. He assured me that they'd talk to the drivers. But since then what I do instead is get an Uber which takes me right to Southwest's drop off right outside their counters. They have "Disabled drop-off" and there are people with wheelchairs right there who come to the car (especially if your Uber driver yells "We need a wheelchair!") There's curbside check-in, they help you through, bring you in to Southwest (where you may or may not have to switch to a Southwest-owned wheelchair). One time the first wheelchair didn't do curbside check in, but he took me in (in the wheelchair), somehow got them to check me in immediately by pulling an agent aside, then we were off to the gate! Yeah, this second way (via Uber, etc) costs me about $25 more + tips, but it's definitely worth it to me.