In the UK, the ATCOs also addon something like the following when instructing an altitude or height.
"BAW123, descend to altitude 5,000ft"
"BAW123, descend to height 2,000ft"
This means the pilot would have to be a really stupid, or very hard of hearing not to notice that what was instructed was not a vertical speed. I don't even believe vertical speed instructions are given like that in the UK, I certainly have never heard anything other than something like, "Descend FL80, expedite descent" or "Climb FL240, best rate through 160". etc - the closest examples I can think of, where it is remotely specifying vertical speed.