Thanks...it's the home of friends...the only reason I can think of for having non-OVP sinks is cost, perhaps? Probably a builder who was trying to save money?
Thanks.
I think it depends on the sink style.
Some of the newer vessel sinks don't have OFP because they're supposed to look like antique bowls etc (check them out on ebay). Mine looks like a big bowl sitting on top of the counter, not like a sink at all.
Most modern, in the counter sinks and pedestal sinks have OFP, but, some of the trendier, more artsy ones my not. Or, some of the older, cheaper ones too.