[Sam Cree]

he would feel better and safer somehow if Gandalf were with him

That's sure to be right.

Didn't you think, in the movie, that when they saw the black riders walking below the weathertop that they should have spotted them from farther away? In the book, I got the impression that they first noticed them at a much greater distance. It was a spooky and frightening image, though, of them all walking up.

[Overtaxed]

Yes, I think they should have. Apparently Strider was off scouting in some direction where he couldn't see them and everyone else was either sleeping or cooking/eating (and lighting a signal beacon, for heaven's sake!)

Which "notice event" in the book is it? There's the one in daylight where Merry, Frodo, and Strider see the BR's on the road from the top of Weathertop. In the movie the one time they spot them is at night. Also, in the book I got the impression that they "felt" them before they saw them.