Was just pointing out the potential. You dont know how many support calls I fielded working at NetApp about thin provisioned LUNs serving virtual exchange servers, and the SUPER CONVENIENT background defragmenter doing its thing making the thin provisioned LUN not be so thin anymore, all suddenly. (In big deployments, where they have a dozen or so virtual servers all living on thin LUNs using VMWare or some other virtualizer, all living crammed together on a barely sufficient storage controller— having them all suddenly decide that they need their full allocation, all at once, all at the same time— makes the virtual server admins have a heart attack and call support frantically.)
You try explaining to a customer that there is nothing wrong with the storage controller at all, and that their virtual server deployment(s) is(are) responsible. Try doing it when the admin gets paid way more than you do, and proudly knows it, and refuses to listen to you. It gets even better when they expect you to be able to get corporate to change their advertising to contain a caveat about windows background defragmentation service when they proudly proclaim the virtues of thin provisioned LUNs.
I’m still a bit sore about it actually. Just be wary of thin provisioned LUNs unless you know EXACTLY what you are doing.