Our clients know it pretty well - it's all about education. The button's called "revert" for a reason, and it's placed pretty prominently on the page.
When we removed the fear of fucking up, they started learning.
Genuinely curious: your clients hack around with Views on their on production site?
I'm not sure whether I think that's insane, or whether I'm simply very jealous of your clients.
Not all clients. Clients are different of course! Should something break it would be immediately obvious, and not all are prepared for that (obviously!).
It also depends on the structure of the site itself.
But some are comfortable changing a title, sending new arguments into panes and stuff like that. Again, depending on structure. As long as the job can be boiled down to a simple point and click routine, they get comfortable doing it. They're not too scared of filters either.
Some are also comfortable setting up new panel variants. It's an extremely powerful editorial tool, when setting up sections with teasers. ("breaking news" sections based on terms for instance.)
The benefits of having a UI to manage core application behavior is lost on most clients. Most are terribly scared of editing a view, content type, or pretty much any other module specific configuration. I speak from the experience of someone whose developed about a dozen or so Drupal sites.