Some people wouldn't notice if that their heads were on fire!
It has been my experience that many people don't say anything out loud in fear that they may put their foot into it but they do notice...eventually.
For some I had to lose over 30 kilos before the penny dropped. With others - even more than that! A few thought after finally noticing the weight loss that it maybe because of illness. Around the 40 to 50 kilo mark I was regularly asked if the weight loss was deliberate (the insinuation being that I was sick). One good friend asked me straight faced if I had cancer...so I told him yes as payback for not noticing my weight loss before (he was a magician - he is suppose to be observant!)...his face dropped with shock so I quickly told him the weight loss was deliberate - then he hit me!
A few will say nothing at all...and go away inspired to lose weight themselves. A couple of people have approached me much later with stories of seeing me lose weight and that encouraged them. People are watching...even if they aren't saying anything to your face!
Pilates? My you are keen!

Best of luck! Go for it tiger!
Kim