[krapp]

It would be unreasonable to expect every company that uses open source software to have a PR accepted for every such software they use.. most companies using open source software are not software companies and don't employ programmers.

It also goes against the spirit of the free software ethos. The end user has the right to use their software as they see fit, which includes not contributing back. If you don't find that acceptable, write it in the license. If they violate the license, sue them.