Maxperson
Morkus from Orkus
The player is not allowed by RAW to say the roll is warranted. Only the DM can say that, and any criteria the DM uses, high DC, proficiency, not an elf, whatever, is reason for a roll not to be appropriate.But as soon as you assign a TN of 20 to the Sage-background, Proficient-in-Religion cleric, the wording of the rules that say that a roll is warranted when the TN is no less than 5 and no greater than 30 would be allow the player of the Brute Barbarian to say "hey, a roll is warranted, oh, I made a 20".