In the age where more and more people want their pictures digitally, I'm surprised that anybody is, well, surprised, that this happens.
Put yourself in customer's shoes. You are selling a service, skill & access to your equipment.
Your skill gives your customers:
-Proper exposure
-Proper lighting
-Proper framing/poses
Your gear gives your customers:
-Complicated lighting and exposure setups they can't accomplish on their own
-High resolution RAW files
-Tons of raw (pun intended) material to work with
Case in point, the music industry is in a death spiral right now because they've been in the business of selling plastic discs. People don't want plastic discs anymore: they limit what you can do with them. They want digital files, i.e. just the music.
I think of photography the same way. More consumers may be wanting, in this analogy, just the music, not the plastic disc. They don't want your prints as much as they used to 10 years ago. They aren't going up on the mantle like they used to. Now they're going on Facebook, into home made movies, slide shows, digital photo frames, etc.
Think of your pictures as a raw material, that your client has commissioned, and that they want to use to build something of their own. If that means a ****ty border, so be it.
Granted this point of view is probably not shared by hardly anybody else here, but that's how I think about it.