Like Kraven said, as you progress higher in levels, you get more points to learn more things (IE Weapons, vehicles, armor). So you can't really give a lower level weapons that he/she can't use. So in short, no I don't think there will be twinking.
PS There was also a segment waaaay back when Huxley was first introduced saying how low levels that group up with higher levels get loads of EXP and higher levels that help lower levels get loads of EXP also. So I don't think anyones going to be staying low leveled for a while because everyone loves there EXP.
