Scratches and superfectas
 

I've noticed that recently at NYRA tracks, after the scratches, superfectas have been added to the betting menu of races.

This seems like a recent change and is a little problematic as the past performance pages, programs or other documents would not note that exotic opportunity but more generally; what is the rule and the logic behind it? I am a little confused because I thought that superfectas were excluded based on the number of betting interest and unless both entries are scratched and two entries/betting interest draw into a field you never have more betting interests after the scratches than before and you usually have fewer.

I think they add supers in NY when one half of an entry is an early scratch and there is the qualifying number of horses.

There can be more horses running after scratches. This happens most often after a race comes off the turf and and Main Track Only (listen in the DRF as MTO) get in. There may be other reasons but these are two of the most common.

This is correct. The rule in NY is that there can't be a superfecta in a race with one or more coupled entries. If part of an entry scratches, the superfecta is reinstated.