Most people absolutely will politely wait. Or, bc they simply are not previously informed of why no sound is coming out, they jump in bc they are concerned and want to help. There will probably be a nervous laugh, and, in my 30 years of experience of stuttering, almost everyone will want to be kind/helpful. For people with blocking so severe they are terrified of having to say their name, they are blocking *because* they are terrified of making others awkwardly wait. It’s simply much more difficult than “just do it.”