At both my last gig and the current one, coffee was available via a Keurig.
At the previous gig, it was declared that you should remove your used cup when your brew was done, and if the reservoir was empty, you were to fill it. There were some people who seldom (if ever) did this, and there was much snark and gnashing of teeth.
At the current gig, we do the opposite: When you open the cup holder, you will have to remove the previous person's cup, and if the water is empty, you will have to fill the reservoir. You do these things because you are incentivized to do so, as either condition is a barrier to you getting your drink. As a result, there is no grousing or emotion aside from perhaps being briefly delayed.
In the former, a lazy person has caused you more work. In the latter, the worst-case is that you lose a trivial lottery.
I think the second way is better.