It is a Hostile Environment out there on the Roadways . . .
Rocks, Litter, and a Multitude of Miscellaneous Debris are bound to come contact with your vehicle at one time or another . . .
As for INFINITIs being prone to being rock Chip Magnets . . .
I'd say no more so than any other vehicle zooming down the roadway is at coming in contact with a road stone is.
Nissan and INFINITIs are know for their " Self Healing Paint "
Google it . . . However ~ it is more about scratches than stone chips