Free: Contests & Raffles.
It could be anything from a WDFW approved feeding station to limit the amount of damage being done to the trees to a poaching operation. Call the WDFW and find out. The numbers makes it sound legit, it would also be a great way to look legit when it's not. I agree with goshawk. If its a legal bait at least you will know once wdfw gets involved. If its not, wdfw should have delt with it by bear season. As stated above, you didn't put it there, but you now know its there, dont put yourself in jeopardy for someone else's problem.
I saw four different ones in gmu 520 like two weeks ago. I looked to see if there was a trail cam and there wasnt. After looking closer i saw that they were numbered. they had pellets in them, and were placed on nice game trails.might be a good place to sit and watch for a bear come august