Board Thread:LOC General Discussion/@comment-25195982-20140718170118/@comment-6053607-20140801212757

Tip for newbie Front Army: make sure you lock your card(s) before you skill up. This has the following advantages:

1) You avoid using a valuable card as enhancer card to skill up your atk or def card in error. Trust me, lots of people have accidentally picked their valuable cards to enhance their card.  Learn from their mistake, lock your card so it doesn't happen to you.

2) Prevents you from accidentally accepting a bad trade (you will get low ball offers for your valuable cards). Again, people have accidentally hit accept trade when they meant reject trade.

3) Prevents you from accidentally selling your cards (it can happen to you).

Cards that are locked can't be sold, traded or accidentally used as enhancer cards. Lock feature is the best for noobs, use it or lose it.