Does Your Logo Work in Black and White?

My friend sent me her new logo last week, and it looked great in colour but turned into a grey blob when printed on a receipt. It made me think about how many marks fail once the colour is stripped away. A company logo design uk team would say every logo should be tested in plain black before it is approved. A wordpress website design agency UK team would add that favicons, footers and email signatures often show the mark in one colour too, so it has to hold up there. So I am curious, have you ever checked how your logo looks without any colour at all?