Not sure where this will appear in the comments but this is in response to David Brush's observations on the location. I personally like the certain/uncertain buttons as the binary choice offers simplicity. You either know the fact, or you do not. If it's reasonably certain, you can always comment in the text - I do not see why this is unsatisfactory.
I think there's a tendency in all of us who deal with genealogy that we want to know the answers and/or want to close off uncertainties - but being happy with these uncertainties is surely the key. I have no idea what the % of people is that die in the parish they are buried in but I am reasonably certain it is well below 90%. You might argue you have a reasoned assumption (he/she was buried in X so he/she died in X) but it is surely more persuasive to say just because he/she is buried in X does not mean he/she died there...for example, one of my wife's relatives is marked in a grave in County Donegal, Ireland when his ashes are in fact in a vase held by another relative in the US.
Embrace the uncertainty!