Very interesting to compare how things are done in India - ranging from their "delay repay" scheme to "can I take my parrot on the train"
https://blog.railyatri.in/8-indian-railways-rules-you-never-knew-about/Example ... On marking up product prices when selling them at stations ...
The Railways Act of 1989 clearly states that the IRCTC authorized food vendors selling packed food items or water bottles cannot sell their goods over the MRP. Any vendor if caught in the act, would be punished with a hefty fine and may have the license cancelled. Railways have a toll free number of 1800111321 to register complains in this regard.
... I do recall some companies in trouble for marking up in hospital shops, and station catering often feels more expensive than outside the station.