Absolutely; I think the bulk of those guys who want to do sustaining engineering are typically the one who got their EE degrees because "it's a good field to be in" -- not because they loved designing things. The same goes for software, and I think it's one of the reasons software today tends to be so buggy -- too many guys working on it think of it as "just a job" and were never particularly passionate their CS studies in school.
Risk should be a consideration if you're volunteering to do something you've never done before, although my experience there is that often times if you manager could really understand how much schedule/technical risk you've just undertaken by committing to designing the warp drive part of the Enterprise, he'd probably just be designing it himself anyway. :-)
Then again, today many companies begin a contract with the assumption that if the specs can't be met, they can always be re-negotiated; I'd be willing to bet that the companies that the likes of Joerg and Jim T. here presided over didn't operate with that business model.
---Joel