Can someone with US I-551 stamp land in Canada and come back to US same day with no problems?

[S&H]

We are trying to find anyone with information or experience in doing this. He has the I-551 pending (waiting on I-751 decision) stamp in his passport, and has the landing
    papers for Canada. He is wanting to do the landing and return to US the same day. We have heard various stories and versions of what may or may not happen... and we are
    just trying to find out for sure. Will he have any problems crossing back into the US with that stamp after he gets the stamp that he Landed? Any information on this would be
    greatly appreciated. He is at 20 months at this point since interview for the I-751 and still we are waiting on US to make their decision... this is why he is doing the landing, but
    we want to know that he can come back.

 

[VVIP]

I-751 Processing

I would like to get all the people waiting on their I-751 to get processed, together, and then we can choose some form of action.
We can sue the INS or maybe send one big letter that has our signatures, with a polite statement indicating our intensions to sue the INS if they don\'t process the pettitons.
Listen people, all the INS is doing is just bullying us around.
I have seen that there are people here who have been waiting for 5 years (and still waiting) for their petitions to get processed.
They could have had their citizenship a long time ago.
We should not allow those INS people to do this or get away with it, especially after they havce cashed out cheques ... i mean they got took the money and they have not performed the service ... in the BIZ world, if a company does this, it can be sued to the hilt ... so i say, let\'s go get\'em and get some monetary compensation from them.