What is the point in defending with your offensive infantry , is exchanging roles a thing in a competent embassy?
If you just have play hammers, it doesn't matter losing some infantry defending... And it's not "offensive infantry", it's both offensive and defensive. Of course it should be avoided as much as possible but... Can definitely come in handy, especially if you are near the border area, or have in-quad opposition with relatively short travel times to you.
Are ghost hammers a thing in standard speed servers?
Yes