Yup. It's pretty common for open source to be used, abused, modified in house and not shared. Just look at Sergey Aleynikov and Goldman Sachs. [0] Further I've seen a shop deploy hundreds of thousands of CentOS nodes to avoid RHEL license fees. Doesn't even begin to scratch the surface of shops not funding FOSS they exploit like OpenSSH, etc. Most of them are stingy, demanding, greedy bastards.
[0] http://blog.garrytan.com/goldman-sachs-sent-a-brilliant-comp...