If feasible, strategy a) would be my preference as it offers two things: first it teaches which field name is reserved, second that it cannot be used. Strategy b) is not user-friendly, and strategy c) is less transparent than strategy a)

a. Adopt a strategy, where users are warned when creating files where field names/variables are given the same names as a restricted word - a warning.

b. Maintain current where users will find out since either an error or occur or nothing happens when they create confusion in this way - a "non-friendly" way towards users.

c. A strategy where field names cannot have the same names as functions. - a restrictive strategy.