notifications when two users (sharing a workspace) edit a topicmap in parallel

[Malte]

My current idea is:
If two users interact with the same topicmap in parallel (and both have editing rights) a notification/message could be shown to avoid unintended results:

The notification could for example be like:
<pre>
Another user / A user you collaborate with / User X has just edited this Topicmap.
To prevent unintended side effects we advise you to <button>reload this map</button>.
</pre>

The dm4-subscriptions plugin and service could be used to create, send and deliver this kind of notifications. I can imagine that in a collaborative environment (the dm4-subscriptions plugin ) could subscribed users per default to "Topicmap" (per type) edits in all of their workspaces.

What do you think?
I see this as an issue we already ship/users will have soon and something like this could be a good solution to it (though it is already quite complex behind the scenes).