It certainly isn't typical, at least among "big name" suppliers dealing with "institutional" customers. For example, I've ordered chemicals from Fisher and the

It certainly isn't typical, at least among "big name" suppliers dealing with "institutional" customers. For example, I've ordered chemicals from Fisher and the composition wasn't up to spec, which I should have known by reading the fine print. But they refunded me $several hundred anyway, and I kept the kinda-wrong chemicals. This sort of thing happens a few times a year (things like the ice thaws during delivery, etc.) and they always fix the problem immediately without asking for proof. Sometimes it's my fault, sometimes it's their fault, and sometimes it's fate-- But they never ask for proof. Similarly, Thorlabs bends over backwards to accommodate customers, and has shipped me free replacements when I broke their $hundreds-thousands stuff by using it in a somewhat out-of-spec manner. Also, any mainstream antibody supplier will reship or refund orders if you call them up and say that their product didn't work well. I haven't ordered raw materials for semiconductors in a really long time, but I assume that any good supplier behaves in a similar way. At worst, I'd expect them to ask for some sort of minimal proof as to why their product was out of spec. Of course if the customer gives indications of being a scammer it's reasonable to cut them off, but asking for replacement of $hundreds is absolutely normal behavior.