Every time this gets posted to HN, the comments go straight for "DRM bad!", when the Bob dishwasher does NOT in fact require you to use the proprietary cassettes.
But the company itself mentions several drawbacks to not using the cassettes. So, yeah, it is absolutely a form of DRM. It doesn’t totally brick your device, but it definitely reduces its functionality.
Scroll down to FAQ, and expand the first question: Is the use of a Bob cassette mandatory?
LE: It's also mentioned in the rewind project's README.
> Credit where credit's due, Daan Tech didn't completely lock down the machine with Bob cassettes. Once empty, you can leave it there and add detergents manually.
A DRM'd cassette for dish soap. This world needs an enema.