Why do companies have a suggestion box if they're just going to ignore the suggestions?

I've worked for a couple of companies over the years that had those and I watched an owner one time come out and open it and take the things out and throw them in the trash. But I would much rather check out Dilbert than that other crap.

Some people just haven't a clue.. they have a genius in their midst but don't realise it... you should be running the company :)

Just giving people the impression you are listening and willing to consider their complaints or suggestions appeases  them just enough. It's essentially a type of red herring.

Print off some DEmotivational posters and hang them over the top.

It gives the staff something to become disenchanted about.