tumill –
I will add that the reason I made this mistake was because on 51st street the BP eruv only includes half a block. However, if there would be a need for those on that block one would be able to carry until 8th avenue (just like 52-53 Street).
Just as people are making up stories that people are carrying in Sunset Park because of the BP eruv so too you are making up stories about people carrying out of the eruv.