Hi Wim, I think you are right that perhaps some Ethernet based applications may break. But perhaps it is worth to observe that wast majority of other applications may happily work on virtual subnet too.
So maybe rather then stopping adoption those who are worried about some specific applications not working in any of today's L2 emulations to document those in a draft. For one it could be nice deployment guideline document to the operators and for the second it may give hints to application developers to fix their code :) Best, R.
