Don't waste paper if you don't need to. Making unimportant things such as paper airplanes, or writing one word on a piece of paper then throwing it out is wasteful.
Villagers will sometime trade for string. Witches have a chance to drop string upon death. Steal string from other players. Use Creative Mode/Commands.
If you suspect a co-worker is stealing definitely tell your boss. Make sure you have good reason for accusing them and aren't doing it just to get them in trouble...
