Please start now. Only squeaky wheels get grease.
Not Variant To Data... that has full checking on it for coercion legality. It isn't a raw Type Cast. I suppose you could get a backdoor Type Cast using the Unflatten From ____ nodes... on refnums. Casting refnums is the heart of the problem. I should have phrased it more broadly -- the two things you can do to crash LV that aren't R&D's fault are moving refnums onto wires that don't match their real types and calling outside of LabVIEW (to DLLs, Sys Exec, etc) in ways that inject back into LabVIEW.
If a user writes a piece of LabVIEW and gets behavior that contradicts intended design, including failing to get an error when they should, that's a bug. Some are small enough compared to the effort to fix such that we let them go without being fixed, but they're still a bug. And changing the one line of code from "FileName()" to "QualifiedName()" is a pretty low-hanging fix.