MyBB Extend SQL error when querying disallowed paramter

[noyle]

See the second link in the quoted post:

I'd generally recommend using paid themes, but if you want a free mobile-friendly one, I'd recommend this theme and a couple other ones here.

The page will return a database error on by={$by} where {$by} is not in allowed options. It's not really a sever problem but will surely confuse users.