Dementors after Harry?

[sam2sar]

No: HPFGUIDX 54063

I have just finished PoA again and a thought occured to me.  Do the 
Dementors have standing orders from Voldemort to give Harry the 
Kiss.  Did they search every compartment on the train?  Since they 
are "natural allies" with Voldemort if they destroy Harry he could 
rise again and have plenty of humans to suck happy thoughts from.

They seemed to have went after Harry at least 3 times
1. on the train to Hogwarts
2. at the Quidditch match 
3. by the lake with Sirius and Hermione ( maybe thats why they went 
after Harry first)

Sam I Am