From the BIP specification:
“Bip300 allows for six new blockchain messages (these have consensus significance)”
https://github.com/bitcoin/bips/blob/master/bip-0300.mediawiki#user-content-Specification
Discussion
Global consensus or sidechain consensus ?
Are the messages intended for miners or miners and nodes for verificatoon, conf, ect ?
There are no side chains as of now so it looks like we are talking past each other. FWIW, my nodes will not be supporting BIP 300 for the foreseeable future
There is a drivechain test net with several active sidechains including a a zcash and lightning clone.
I asked a simple questions about bip300 design and you are bailing out. If i'm correct, miners don't need you to run it on your node. Bip300 consensus is describing consensus among other miners, messaging and voting is among miners, not nodes and miners like blocks, transactions ect.