Whenever my husband and I ride our horses, he spends a good amount of the time nagging me about letting my horse have an occasional snack, amongst other things. If we've stopped for a minute or two, I'll let her put her head down to eat a little grass. I don't think it is a big deal, he thinks that it is terrible and I get to hear, "Don't let her do that." He sees it as her being "disrespectful". I see it as, "I'm expecting this horse to work hard for a 2-10 hour ride, I should let her snack a bit if it doesn't interrupt the ride." I do not let her do it all of the time.
He's the same way about letting them drink at creeks. He always stops his horse before I stop mine, and tells me, "That's enough, she doesn't need that much." I kinda figure we're having highs in the 80's and 90's these days, I'd like her to get all of the water she wants/needs.
How much do you let your horses "snack" on the trail? Do you see it as a huge problem? Does it bother you if other people allow their horses to?