Does SOO setup in BGP and EIGRP compromise redundancy ??

Guys,

I have been reading articles about soo for both BGP and EIGRP.one thing that is not mentioned clearly is that if this solution creates another probolem when set up.here is the link about soo in BGP.same thing would apply to EIGRP.My question is that if you apply soo with the same value to prevent loops on PEs and the backdoor link breaks ,then you cant get  PEs to talk to each other via MPLS as when the routes  get advertised toward another PE  are tagged with SOO value. Hence the other PE would not send them to its CE when receive them.

PE2 <-------->PE1

 ^                     ^

soo 1:1           soo 1:1         

 |                      |

 |                      |

CE2 <--------->CE2

http://www.cisco.com/c/en/us/td/docs/ios/12_4t/12_4t11/htbgpsoo.html