That might have helped if they actually caught fluids in the carry on. In my experience (accidentally left bottles in carry-on several times; always found out myself after passing through security with no problems) they don't seem to do that.
It's inconsistent. I've had various things denied in carry-on (e.g. jar of jam, snow globe, etc). A TSA agent even told me that snow globes were not allowed even in checked luggage, which I found out later is false. I had to find some way to mail the snow globe to myself from the airport.
