I see these things as a risk/reward situation; in this case the risk is that you put time & effort and a bit of money into tubing it, for the potential reward that that fixes it, but the additional risk that it was wasted effort... vs spending more money for the likely reward that it does fix it. If I was dirt poor I'd likely consider my time not worth as much as the difference in money, but any more it doesn't take a lot before I say "not worth it, spend the money and be done with it". I really don't like having my tractor time interrupted.
Any engineer supplying product to the government (in my case, Army) knows well the "probability/impact" risk tables, that accompany every risk management analysis. Anything that's either "high probability" or "high impact" requires a resolution, and those which are both are usually gating items to proceed to the next phase of a project.
In other words, if you tell them it might blow up and cost them $10M, but the probability of occurrence is low, they're going to want to know what you're doing about it. Likewise if you tell them it's definitely going to blow up many times, but cost to repair is only $100. But if it's $10M per repair and it's going to blow up every 5 weeks, your project ain't getting off the ground.
