When our horses lean toward the patch of tall grass when we're leading or riding them - it is a question they are asking: "May I have a bite of this?" - Our answer can be "no" when we direct them promptly away and send them on. Or it can be "maybe" if we do nothing - or even "yes" when we give them the rein or the lead and let them stop to munch. But what we do is an answer to their question and if we allow something and then "change our minds" or realize that suddenly they're doing something (that we allowed) and discipline them for it; we are confusing them and likely frustrating them on many levels. Horses do not know what is right or is wrong - they know what we allow or do not allow. They know what we supply as answers to their many questions each day. It is our responsibility to be clear and consistent!
