We’ve often had camera ops drop the cards off with us, we have pulled them straight off the card in the past (not using the XF utility) with no issues at all, but only in the last few months, and once maybe about 8 months ago, it’s happened.
On our last shoot we pulled footage using the utility software and the audio/video sync slipped across the single footage clip, so I’m not sure where the problem stems.
I haven’t managed to try it on FCP or anything, but our main office workflow is PremPro, hence posting in the PremPro forum.
Let me know how you get on with the C300 footage.