I see it as a bit more dangerous/annoying than that.
Sure it might bring little harm, but what if I'm trying to sell something to the client, paying attention to the politics and all the other crap you have to be mindful of and, all at a sudden, some as*hole desperate to make his sales target gives them a call, telling them god knows what and possibly jeopardising it all?
There should be a clear distinction between relationship ownership and sales attribution. If you own the relationship, no contact with senior mgmt of the client should be made without you knowing about it. This does not mean everything that it's sold to that particular client should only have your name attached to it. If another partner with a specific specialisms contributes to sell them something (by taking part to a meeting or else) then he should get some credit too