grumbler
Prince
You have found a flaw in my gripe. It would be better if Sentry also fortified you, but woke you, where as the regular Fortify meant "I don't care to move this unit". I can't count the number if times I've fortified a unit that I expected to come under attack soon, and then the enemy wandered away instead, and then I forgot to move that unit, and that's what I was really railing against. I'll correct that on my own list.
I think you would be best served to get rid of that particular gripe completely.
Sentry does fortify your unit. The fortification bonus is not dependent on giving the fortify command, but on the unit staying in place. Even if you only hit space each turn, you'll gain the bonus. You'll also keep the bonus if you wake a fortified unit. You'll lose it, if you move the unit or order it to perform an action (e.g. attack, pillage).