Likewise, never heard of a "VMC Approach" as such, but here's my take on it.
It may refer to an Instrument Approach Procedure which happens to be carried out in VMC, in which case you must still comply with the full procedure as regards radials, step downs, speeds etc and you remain under positive ATC control at all times, including traffic separation, with assured terrain clearance.
During a visual approach the flight remains IFR but you are left to your own devices, and this includes traffic/obstacle separation. Hence you may well be asked for confirmation that preceding traffic (if any) is in sight before the visual is approved and will remain so until touchdown, although traffic information may be passed to you subsequently.
Just my thoughts...not sure if this is what they are getting at.