I don't think I've ever seen someone like take another persons OC and use them themselves in subsequent RPs, at least not without consent and even then very rarely.   That would pretty much universally be heavily frowned on.  Even making a parody or clear espy of another persons OC would raise many eyebrows. 

One way you can help avoid that too is to cut back in your characters influence in an RP if you feel you may not be able to continue.

If there are seven folks in an RP and one guy RPs as squad leader, meaning until he/she posts again no one can continue the RP, if he/she ghosts someone, usually the GM, will have to address that characters absence somehow.  So if you're going to have to drop advise the GM or throw up a quick post about why your character is either out of the RP or inactive for some time.

Maybe you get injured and will have to seek mid to long term medical care in the next city.  Maybe you get a message from a family member and have to leave to attend to family business.  Maybe you just disappear in the dead of the night for reasons that may or may not be explained later.