Hi!
As the title says, what happens if i get an address wrong? Do the coins get lost?
If that's what happens, why not change the code in Bitcoin, so that if the bitcoin network cant detect that address, returns the bitcoins to you?
There's no way to cancel the transaction. If ever I receive a free bitcoin I will not send it back. I doubt if some body had done it. It is always better to double check transactions and bitcoin address before sending it. All you can do if ever you sent your bitcoin to a wrong address is to check the numbers of confirmation done on block chain before the stranger receives your free bitcoin.