There is no way to detect a illegal transaction.I doubt even in future this feature will ever be implemented.How can you decide if a transaction is illegal ? Volume of the trade ? Bitcoin address associated with it ? All the blockchain does is process the transactions by keeping them public regardless of who or what is being the address is used for.
I think there's no reason for the blockchain to detect some illegal use of bitcoins or in any form of transactions along the deepweb..because first of all bitcoins are anonymous ,also the transactions on deepweb will be more anonymous..before entering on that site many people hide their ip 10x or more to not be trace in any transactions they made.
That's incorrect. Transactions will be on the blockchain regardless of how secure your Tor network is. Doesn't matter if you're on deepweb,a public ip or 10 tunnels down the secure server,your transactions will be anonymous and public only.
the weakness of bitcoin is the transaction can be traced, if (just for an example) FBI knew who's the owner of the address,the transaction could be traced where it's going,and they will find out more information about the address on the internet,although the money still can be hided by exchanging it to any altcoin which have anonimity better than bitcoin