YANBU - I went for a walk with my 4 yo DD and our West Highland White Terrier this afternoon. The Westie was abused by children prior to us owning him, and is quite headshy as a result. Also, he is a little scared of children (although generally absolutely tolerant of our 3 children who are 4.4, 2.8 & 1.0).
We were walking along a pavement, and there was a ?5 year old boy on a bike. He saw the dog and started to rush to him. I said "No, no, no, don't...." but he wasn't listening at all. I knew that our dog would be startled by his approach, and didn't want to risk him 'warning' the boy, and getting the blame. I had to say very firmly. "I SAID NO!". The boy stopped, and said sorry.
However, if Alex hadn't been on a lead, and I wasn't nearby, the boy rushing in to pet him could have been nipped because he ran over and lunged for Alex to pet him.
Of course, it would be Alex that got the blame.