We do have people push on their first day here at Gridium and I think it's really beneficial. The new engineer sees how we work, and the rest of the team sees that new name in the git logs, on chat, and everywhere else. It sends a strong message that there is a new member of the team who is going to be contributing from now on. It helps to establish cultural norms (everyone makes a big deal out of that first commit which is fun).
I really like the effect it has on our team. Even changing two characters in a string feels like a big deal and that's awesome.