This is a very popular website( irctc.co.in) in India which is being used by more than 20 Million Indians to book their railways tickets.
But here's something I've found:
When you book your ticket through this website, you will have to add your age and check the box in case your are a senior citizen. I find that this can be easily done just by setting auto-detect that checks the age filled and applies the filter if the applicant is a senior citizen. This would be fairly easy for a website that gets more than 120,000 users booking tickets at the same instant, however I would like to know if there are any other reasons for which this website has this feature?