Years ago when I was one of the few people among friends and family that had good internet and a credit card, I used to book a lot of tickets for others. Out of frustration, I wrote a simple python script that automated the process of booking tickets at 8 in the morning.
It would log you in, fill in the passenger details, payment mode etc.. and boot you into a browser for the final bank transaction screen. It was fast because it wouldn't actually wait to download the html screens before submitting the data. It would scrape the main page's date and sync itself with it to submit the booking exactly at 8am. I was able to finish a booking in less than 30sec.
After spending a few days prodding their system to make this hack work, I learned just what a mess their backend was.
They have a form variable called 'clickCount' which they increment and pass around on every page. This is how they 'detect' that you clicked a link twice and helpfully log you out.
Their validation and actual processing of passenger genders is case-insensitive - they accept either 'M' or 'm'. However the final ticket printout you get will show all passengers as female unless the gender you sent in was in upper case (curiously though the actual official print out pasted on the train when travelling contains correct genders - I have no idea why).
I presume many people had similar scripts to what I had and so eventually in an attempt to circumvent it, they introduced captchas. Turns out the captchas didn't actually work.
I know this because my script continued to work for a long time and only a few months after they introduced captchas (when I visited the website the normal way to make a booking) did I even know they introduced it. I can only presume that if you didn't actually submit the 'captcha' form variable then they didn't bother to validate it. So the irony was that the people booking tickets the normal way suffered while the rest of us working around the system were rewarded.
Finally they realized this at some point and threw in the towel and just banned quick booking altogether from 8-9 because they couldn't figure out any other way to actually solve this problem. So yeah, I'm probably part of the reason that happened (though by no means the only one who did this type of hackery,I'm sure).