I get the point you are trying to make, but I think these circumstances are different. Your point is valid if you are talking only about consumer users. However

I get the point you are trying to make, but I think these circumstances are different. Your point is valid if you are talking only about consumer users. However, any enterprise App account is going to be run by a (generally speaking) technically literate administrator who decides what features to enable for their App users. As long as Plus is sold as 'beta' or whatever, there is no real risk to opening it up to App accounts - regardless of whether they are personal users or enterprise users - because it's a conscious opt-in process being made by technically literate administrators. And as many of others have already said, there is a big downside to treating your App administrators as second class citizens who can't make their own decisions - you lose the very people who have an appetite to try new things (why else did they move to Apps instead of using MS Office or whatever), and who are generally drinking the Google Kool-Aid. It's probably not the best analogy, but I think it's like Apple releasing the iphone 5 and saying 'Anyone who bought a previous iphone within 30 days of when it was released is not allowed to buy the new iphone 5'.