http://g7cpug4k6ydyq5dlxrji35xnfq5n5rba3n7holux4tmdsm42ju543tad.onion
Nobody can get a copy of the blockchain from a normal user, but they can from the reachable node that accepts incoming connections. One example is remote seed nodes that are hardcoded in the full node software . When running a full node, we already have "trusted" remote (or reachable) nodes included. One might wonder why every node can't be a remote node, thereby helping the network and other users download the blockchain from them.