There are many special versions of torrent tools that allow disabling uploading. If course you still have to upload your requests "please give me block 1234 of file XYZ", which some tools include in the transfer rate shown and others show separate as overhead or meta transfer rates. However, no actual file contents will be uploaded. This is important for some jurisdictions/nations. While both downloading and uploading content is illegal, uploading causes more "damage" ( it's legally easy to claim proliferation of the uploaded content, multiplying the financial damage). Also, in some countries, it's either but legal to track user downloads at all or not in a manner that would provide court-proof evidence. Proving illegal uploads is very easy: the legal company will simply use the p2p network itself, but record which blocks were received from what IP address at what time. This list in many countries is sufficient to get a court to order the ISPs to share info on who owned that IP address at that time, opening you up to a lawsuit.

Thus example is how it works in Germany and must other EU countries. The exact approach obviously differs, because everyone has variations of privacy laws. E.g. not every country makes isps store IP assignment history for longer than necessary for billing purposes ( usually a month), whereas in other countries isps hand out that info even without court orders...

Educate yourself and act smart. There is no magic protection when doing p2p piracy. Luckily, most companies do not care to pursue pirates. Others ( like kalypso media) are infamous for having partnered with legal companies whose sole purpose is to generate income by chasing pirates with intimidating and expensive "pay 800€ now or we sue you in court for millions" letters.

It is 100% possible. Our school network at uni (including dorms) had a very strict no illegal seeding policy. It was possible to tweak uTorrent settings not to upload but if you messed it up, you were without internet for a day and there was a 3 strike policy.