Thomas Dalton wrote:
Of course, it's much quicker to tag something than to check it. I was working on an article earlier that I added references for the bits I could find and added a {{fact}} tag to one bit I couldn't verify, although it seems right - the hope is that someone else comes across it who can check it.
If you looked for a reference and couldn't find one, I think it would have been better to remove the statement, rather than just tag it.
The "although it seems right" part is the important bit. I think it's appropriate to leave in unsourced stuff that isn't controversial and one is either reasonably sure is correct or at least one realizes that they don't know enough in that subject area to have the faintest idea whether it's correct. This is a collaborative work-in-progress, it's not necessary for any one editor to do all the work on an article or to leave an article in "perfect" condition at any given time.