The attacks should cease when you've cleared out Dawnguard's main quest.
My question is why do they start at level 10 regardless of whether you've started the quest or not?
Am I playing a fragile character/stealth character that won't get better until higher levels? No problem; I just don't do Dragon Rising, and I don't have to fight any Dragons until I want to!
Get to level 10 with DG on the Xbox? SUDDENLYVAMPIRES! In much the same way that Skyrim seems hellbent on *forcing* you towards the Mages Guild and Thieves guild (Main quest and several side quests are all guilty of this) DG doesn't give you any damn option, it FORCES you to do the now somewhat arduous questline (Soul Cairn AND Black Reach? Gimme a break...) if you don't want the constant hassle of vampire attacks ruining the use of Fast Travel, which
is also a feature of the game, for all those people bleating about it being 'a feature'.
Skyrim is supposed to be about options and choice. And no, uninstalling Dawnguard is not 'an option', because then I can't play my main character, and I can't use all the non-annoying parts of the DLC
which I paid for, thank you very much. If I don't start the DG questline by speaking to Isran, I shouldn't get Vampire attacks. It's that simple. Then everyone wins. Those of us who hate being mercilessly hassled by crap we didn't ask for get what we want, and those who think the random NPC slaughters 'add depth' get what they want. How is that so hard to understand?