MacBuildServer created at least one of the certs they use for signing inhouse/universal distribution apps on 2013-05-15T16:48:45Z, and it has not yet been revoked. If it does get revoked, they can just remove that part of their service, and continue to allow people to upload their certs, keys and provisioning profiles for building server side. (o.O)

Once MBS becomes more popular, Apple will have to react to prevent others from abusing this. This is the first real test I can recall of their enforcement policy. Honestly, I can't see any enterprises that rely on iOS internally risking TOS violations in a similar public manner even if Apple decides not to enforce TOS with MBS.