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.
What he did seems right. He was able to make a judgement based on the
trends in the rest of the article. I'm assuming that the unsourced
statement was not particularly negative, so why not give others a chance
to look.
Ec