Look up the definition of "discrete". It does not mean private, just separate and distinct.
Others can still hear you but you are unlikely to hear them. Thr chances of someone being heard by you randomly is less that 0.5%. Of course, they could find your PL filter, enter it into their radio, then call you, and it would be legal in a d**khead kind of way. Lets hope THEY are few on our GMRS.