Invalid syntax can pass Validate if it's in part of an expression that is not evaluated

[lognaturel]

This limitation is described in the README at https://github.com/getodk/validate#how-validate-validates but I think it's worth calling out in an issue as well.

enketo/enketo#1097 has another example of a form that passes Validate but has bad behavior because of an or or.