The reasons for including a failure mode where there is no effect usually have more to do with the system around risk management than with the risk itself (which could be neglible and thus eligible for exclusion of consideration in some cases).
I can still imagine multiple entry scenarios for such a case:
1. The risk had to be listed to show it has been considered (possibly due to a previous auditor requiring inclusion into the file due to observation of the failure mode in actuality (or fantasy)), even when its effect is deemed to be zero by the organisation.
2. The FMEA has led the risk to be controlled (designed out if it is severity), with the team deeming there to no longer being an effect, but entering it into the original severity column (or only using a single column approach).
3. There is a checklist approach for risks which need to be entered, but due to the scope or subject of the FMEA, it could never come to fruition. Result: lowest classification you can give.
4. There is no clear linkage of failure modes in the foreseeable sequence of events, thus a failure mode may occur for the process but the chain breaks before you get to customer/end user or the part of the assembly plant which relies on it.
5. Inexperienced Risk Management Team makes entry in illogical manner. What it says is not what they mean, or system cannot accomodate what they mean.
Currently we have only severities assigned. Expanding it to the failure mode itself, the entire row of information on the risk, the full risk management system it came from and eventually the actual product and company is needed to give further advice.
Well as an example I encountere, a faliure mode like this : missing parts in the box in the packaging station. Such failure mode would have absolutely no effect on the final customer if we as tier 1 sell it to the vendor first.
So what do you guys think about my first question??
I think this is more a confusion between FMEA and risk management.
From my experience several manufacturers confuse the two. As a result, I often find lines from a (hazardous) situations that does not cause any damage to the patient, the user or the environment. Those should not be included in the risk analysis list but should, if necessary, be addressed in the FMEA process.
For my part, the AMDEC is a tool for doing the risk analyzis but is not the risk analysis.
Typically the case of forgetting a component in the box must be dealt with in the FMEA and give rise to a CAPA outside the risk management process.