I have. I mentioned it already in a different thread. It was a CRJ700. I was the first to board in the economy cabin and the first three rows of OHB space in the economy cabin were filled with FC passengers' bags. (I have also had the experience of being seated in FC on a CRJ700 and putting my bag in the OHB in economy because all OHB space in first class was full). This is what makes me wonder what might happen when C+ starts if C+ passengers find the advertised "dedicated" OHB space has already been filled by the first class passengers. Maybe it won't happen, but it could get interesting if it does.