After I checked in today at the airport I asked the attendant if I might have received the upgrade i asked for. Instead of just a simple no, I was suddenly told that the Bass Guitar on my back (in a soft case) would have to be checked in with the regular luggage. I was stunned to say the least, especially after the whole "United Breaks Guitars" fiasco. Soft case electric bass checked with regular luggage? I asked if I could "gate check it" if it couldn't fit in the overhead. But she was adamant that the bass guitar should be checked in with regular luggage. "To big to gate check" is what she said. (I have only had to "gate check" 2 times in 15 years of constant travel, both times were with United)

      I refused to check my bass in a soft shell case and asked for a supervisor.  She got on the phone and talked to a few different people while the other woman working with her tried to look up United policy for guitars.  A supervisor finally showed up and the story changed from having to "check it" in to  " United Airlines will not take any guitar in a soft case onboard at all ". They blamed FAA regulations and TSA and measurements and how it was my responsibility to know that United Airlines now had a zero tolerance for electric guitars in soft cases.   Well, I realize that now. I won't make that mistake twice. Either will anyone I know or work with.        
         So ,we were at a stand still. It looked like I was going to miss my flight and have to stay in a strange town where I know absolutely no one.  (On a side note ,I had flown into the same airport on Delta in the same model jet 3 days earlier. It was a full flight and my Bass as well as a guitar fit in a overhead with out a problem or sigh from any Delta staff)
  I was at my wits end. The staff at the desk had no suggestions.  After feeling like I was going to have a nervous breakdown I had an idea and asked if I could bring my bass on board if I disassembled it into smaller pieces. They all agreed that they thought that would work.  So I borrowed a screw driver from the supervisor and took my bass to pieces.  I decided to put the body in my luggage so it wouldn't get all scratched up floating around in my soft case with the bass neck. We bent the case in half and the supervisor wrapped tape around it so it would stay in that shape to fit dimensions of someones suitcase for an overhead compartment.   I now need to take my bass to a tech to have it properly reassembled. Thanks United.

At one point before the supervisor showed up I called United customer service to see if I could get someone who might be able to help me. The representative who talked to me on the phone suggested that I just needed to give the attendants some money ,that I needed to pay them to let me bring my bass on board as "carry on". This was such a ridicules experience. I considered recording all conversations when I was first confronted and I now wish I had.

Some people have suggested traveling with a hard shell case. It is just not realistic for one offs ( Flying in for one show). For some reason guitars in flight cases seem to get misplaced easily and end up at the wrong destination. Maybe it's how they pack the planes. I don't know I've just seen it happen to many times.

I looked up United's guidelines for musical instruments. "the total linear dimensions (length + width + height) do not exceed 45 inches". This excludes all guitars. I have one of the smallest electric guitars made and I measured it (without a case )by United's formula it comes out to 47 inches.

Edit: I used to travel with the bass in a hard case with regular luggage. The problem I had with it was that the airlines kept loosing my bass. The day of the gig would come around and I'd be in Detroit while my bass would be in New York . For overseas trips I always use a flight case but for domestic flights it's a real gamble that it will be there when you need it.