Block commands are not the solution I'm describing, sorry.

If the Block command is the network's only available abuse prevention tool, then chat network has failed to do a good enough of job of implementing anti-abuse protections.

(I'm aware that some people don't believe in network-level anti-abuse protections, and I'm not going to try to convince anyone to agree with me. This is just how I evaluate whether a given chat network is accessible to me or not. XMPP is one such network, and doesn't have any, so.)