Yann, Unfortunately sybil attacks [https://en.wikipedia.org/wiki/Sybil_attack#Description] would prevent this from working... even if there was some way to prove that an entity performed the transaction validation. Proving the relay of transaction data to others is also vulnerable to sybil attack.

-------- Original Message --------
Subject: [bitcoin-dev] Improvement Proposal
Local Time: May 30, 2017 8:48 AM
UTC Time: May 30, 2017 1:48 PM
From: bitcoin-dev@lists.linuxfoundation.org
To: bitcoin-dev@lists.linuxfoundation.org

Improvement Proposal

To allow users devices (including mobile and/or IoT devices). to connect and some how participate in the same BTC bock chain network without mining.

The incentive for this participants can be a lottery schema, running in "parallel to mining in the same network" and in the block-chain.
Rewarding some lucky participant user (and/or miner?) randomly every specific period of time.

Participants will pay the price on each connection round.

Yann