in theory the 1299 can handle excessive brake inputs through the lean angle-sensitive ABS; only a handful of bikes on the market now have this technology.
the salesman at my dealer claims that at a demo, he could do various ridiculous things on gravel and wet surfaces and the bike wouldn't go down.
There's trail braking, and then there are mid-corner emergencies that happen in real life. Like going through a turn and suddenly finding a deer standing there (happened to my friend and his 1098 went down right when he braked).
Can you just grab a fistful of brake while leaned over, on a 1299S? I hope the system works as well as Bosch claims it is.
There is no ABS in MotoGP (or Formula 1) - all braking must be 100% manual. ABS is permitted in WSBK but I'm not sure all riders use it.