Not a myth. College Board has a blanket ban on QWERTY keyboards in tests, so TI Nspire line has ABCDEF keyboards
But then, a lot of things about the College Board are pretty nuts: It is the reason that graphing calculator companies can continue to scam the public by selling overpriced machines running at absurdly low speeds (Their most popular calculator is a 6-15MHz Z80, with 48-128K ram (but YOU, the programmer, can only access 24K): That's pathetic, and yet you can buy a chromebook (a LAPTOP capable of running the famously resource-hungry Chrome) for the same price). The Plus CE did a bit to improve this, but it's still less capable then the phone in your pocket: That is inexcusable).
The Nspire line isn't that bad.. It's not high-end by any means (it's still a damn calculator), but it at least got the lineup to 21st century.
Even in BYOD netbook world, you can bet all social networking and messaging is blocked at the web filter. (Sometimes time-based restrictions open it for lunch and after school, sometimes not).
...Which is why they get away with it. But the calculators are still absurdly overpriced.
Besides, any student can load all sorts of software onto those calculators fairly trivially.