Define "fully charge".
I leave my iPhone to charge overnight and sometimes up to 24hrs, No problems.
Fully charged there really means Overcharged I think.
Most chargers (or all ?) are smart chargers that either shut off at 4.2 volts or switch to some sort of trickle charge.
I think what they mean is just not to hook some wires to a power source and pump the battery with all the juice it can take.
I've been using AW batts for over two years. My oldest current ones are 5 AW IMR 18650 that I've been rotating since November 2010. I use a Pila charger (also two years old) and it charges to 4.18 every time and I pull the batts from the mod anywhere between 3.5 and 3.6 usually. I think smart mods like the pro-vari shut down when the battery reaches 3.3 volts.
Anyway for the OP you can charge anytime you want. Sometimes mine are still at 4.0 volts and I throw them back on to top off up to 4.2 again. And since they are still going two years later after being used every single day I can say that no harm will come.
I also leave them on the Pila charger overnight as well (sometimes longer if I forget) with no issues.