I wasn't aware that the person at the Fly-By lane was a Southwest employee; I never noticed a WN logo (but truthfully I have't paid much attention since I'm not A-List). This seems odd to me since that lane is shared with other carrier's elites, and I do know that when the checker was out at the beginning of the line it was an airport employee, but I'll assume you know what you're talking about. I do know that TSA dumps regular passengers into that lane when busy to even out the lanes, pretty much making that person's job irrelevant.

Since this issue is important to you, I'd suggest you send WN a letter… for what it's worth.

I think it varies by airport. Some are stricter than others. At some airports multiple carriers used the same express lanes (ATL for example) and there are airport employees directing people. But at the ATL South checkpoint Uniformed Delta employees enforce the lanes and have been known to direct non Delta passengers with status into the regular lane.

Fly-by security
 

The MDW Fly-By lane is essentially a Fly-By for the ID check only. It then merges back in with the general lanes before screening, rendering it quite useless. The current set-up of the lane is by far one of the worst in comparison to the many incarnations over the years. The best set-up was when the Fly-By was located on the far left and led into the screening area that dumps out into Terminal A. Hopefully, they will shake things up again soon.

Is there a ATL Fly By lane on the south (Main) checkpoint? Where? I used to use one but I think its a solely a handicapped entrance now and I'm always directed to the smaller North checkpoint where its basic amounts to nothing special. Thanks

Yeah, it seems odd to me as well that WN is manning the flyby station since it applied to Delta and others as well. Maybe it's because WN accounts for the vast majority of the flights out of MDW? Not sure.

I honestly don't think a letter will do much good. I'm sure others have sent letters about this. I can't tell you how many times I've commiserated with other A-listers in line about this.

I've applied for pre-check and hope to receive a KTN soon so hopefully this will be irrelevant soon. Was waiting on the invitation from WN to opt in, but it never came, so I applied. Should have my head examined for not applying directly to TSA sooner.

Yes. Was just there two weeks ago. It's the lane on the left side when you approach the checkpoint. At least is was on my last two trips there.