I cannot even begin to stress to you how very wrong you are. They will know, hell if by some stretch you aren't lying about hosting 50 players trust me they also knew about that, but where it was just a temporary thing they let it slide. They know you are torrenting right now. I've worked for the local cable provider here, and they are nowhere close to Comcast - and we had monitoring software for internet service that would track exactly things like this.  

You might last a week or two at a heavy use, but you WILL get shut down.  Not just your Minecraft server but also your parent's internet.  If you seriously want to do this, get business class internet and a static IP.  And tell your parents. Way back when I was a young lad I tried hosting a BBS using the family's phone line. Did not end well.  I took on a few more chores and ended up getting my own dedicated line.

Think about it this way: Say your town provides water service for a flat monthly fee, it's usually based on # of bathrooms.  Sure, maybe you filled a pool at the beginning of summer and they didn't say anything. Doesn't mean you can open a water park.