student/disabled can buy/validate non-student/-disabled
Stundets and disabled can buy and successfully validate non-student / non-disabled tickets:
- customer is student
- customer buys ticket t with student false
- now validation request for t comes in and customer says they are a student.
https://moodle.rwth-aachen.de/mod/forum/discuss.php?d=160091#p259676
Doesn't make much sense imho (customers don't even have a student flag) but this is apparently the spec.