Because FF, I have yet to meet an IR holder who does not have Mode S. The IR holder is virtually guaranteed to be flying there own aircraft and will have made sure they complied with the rules a long time ago. I have had Mode S for more than 2 years.
The average club rental that scrapes by as IFR capable with some creative thinking is what the average IMCR flyer is flying on the whole and I have seen very few of these Mode S equipped.
It is my understanding that the transition period is for VFR not IFR.
