I'd been toying with the idea of what RPN calculator a kid could use at school here in the UK. I thought the sticking point would be that most RPNs are programmable, but turns out that isn't an explicit exclusion on the JCQ calculator guidance for GCSE and A-level exams. They can also use graphic calculators. There is a hard no on CAS. The HP-15c seemed the least likely to cause issues with invigilators, so went for this. We'll have to see if it works out though.
