Vampire Spawn Domination

[Rainbownaga]

My campaign contains a PC with a slightly modified vampire spawn template, and I am planning on including a vampire spawn NPC who will effectively act as just a low-level vampire.

The problem is that they appear to good at this. A vampire spawn has a dc 14 dominate attack at caster level 5. What is to stop them from converting virtually everyone in the village into minions with 5 day duration, and then refreshing as necessary?

Sure, at times they will fail, but how often will their dominating trigger any form of retaliation that would be of any threat? Is there something I'm missing because this seems like a rather understated power of the vampire family.

Worse yet, the vampire spawn character class includes this ability at an even higher caster level.

[Lysander]

Well, here's the paradox. The vampire's dominate person ability is a single-target gaze attack with a range of 30ft. You have to see it to be affected (so if you know there's a vampire you can avert your eyes to avoid being dominated).

Vampires cannot entire sunlight. So to see a vampire's eyes you'd have to be in artificial light either indoors or at night outside.

In the Middle Ages artificial lighting was expensive. Most people stayed indoors in their homes after dark.

Vampires cannot enter a home unless invited. So at night when the vampire is active, just don't invite strangers in your home and vampires can't get you.

But the real reason a vampire wouldn't dominate a whole village is that it would blow their cover. Vampires succeed by going undetected. While having an entire village under mind control would have some perks, other people would notice that they're acting strangely. The king/church/other organization would send powerful soldiers/magicians to investigate and the vampire might get killed. A vampire is far better off controlling the mind of one reclusive wealthy person, and simply living it up in their mansion.