Think it's unfair to call it a cheat. Different fps levels alter the game mechanics in different ways. 125/250 have benefits/disadvantages over 333. I was playing a bunch in a deathrun server earlier in the year, and they'll toggle between all three to maximize the advantages of each. 125 for example will have benefits over the default 85. Is it fair to call that a cheat?
Ultimately I think it boils down to what the admins/owner of a server allow/disallow. Expecting everyone to think 333 is disallowed because of the last line is dubious, especially when other servers/gametypes allow or even encourage it. It should be clearly stated as a rule.