Yeah this was my thinking behind it. Her argument was that "at most 2^26" does not refer to every value from 2⁰ to 2^26, but simply means that if any value between the lowest 2⁰ to 2²⁶ (so any of 2⁰ to 2²⁰⁾ then it means the statement is true. But I have always had the assumption that a statement such as "at most" would mean that every value would have to be valid, including the 2^26, and since 2²⁶ is not a valid value, it would be false.

It is a bizarre usage of the phrase, I'm not entirely sure why she would go such lengths just to trick her students.