This is coming up quite often with low states PLO opponents. They will call instead of get their stacks in on the turn. Even though they have committed most of their stack. Then the river completes the many draws.

This is an example. I bet small on the turn to induce since he is agro on flops/turn. He potted, I repotted and he called leaving himself 1/7 size pot bet on the river.

http://www.propokertools.com/simulations/show?b=Jc+3h+8d+Ac+&g=oh&h1=As+Ah+Ts+2d&h2=9s+Th+Qc+9d&s=generic

The river comes a Kc and my opponent will probably check back all two pairs. But they can also have flushes, and maybe straights. So I bet.
Is there any argument for this being a check fold?