What is being asked for is not an invalid implementation. It does not, in any way, impair SQL Server from working. If it did, your argument would have basis. What SQL Server 2005's behavior does do is impair the manageability of those database servers, even for legitimate DBA-related activities, when there isn't really a gain on the security side. Security is always about trade-offs and I can understand why the SQL Server did what it did. However, I happen to disagree with that choice and apparently someone had second thoughts if there's now a hotfix for detach/attach.
Gift Peddie, let me assure you that this isn't just some "network admin" wanting to impose control without having thought this through. If you go back and look just a wee bit, you'll see I have a pretty solid background in SQL Server, especially in SQL Server development, performance monitoring, and security (the latter is what I've concentrated on for the last few years). If you have any doubts to the that, please check my article list on this site. I don't point to it to blow my own horn so much as to point out that I've looked at it from an angle more than just as a network/security admin, which is the strawman you're trying to use.
K. Brian Kelley