Echoing what Alex said, I think it's ok.
The only negatives I can see, is if:
- The number of possible values under that particular value is large.
- The boolean column is your only clustering column.
For example, keeping a roster of people in your co-ed softball team (or even a league, for that matter) wouldn't generate enough rows to be a problem. But if a large social network site implemented it for their user database, that likely would not perform well. Again though, this is only if it's the only clustering key.
But in your case, with it being one of multiple clustering keys, I think you'll be fine.