The chances of whoever substituted waste oil for food grade oil being caught may be reasonably high, although proving criminal intent may be a different matter.  The likelihood is that he/she will have few assets and little appreciation of what consequences could have flowed from their actions.  

The problem in today's world is that a relatively petty act can have huge consequences for very many people - and the taxpayer is their only hope for any kind of compensation.  The "markets" cannot solve the problem because even if the offending company is closed down, their is no prospect of their being able to compensate those damaged by the episode.

notes from no w here