why snow fairy cant cross the border, while in the 1st movie they came to pixie dust tree?

because movie creators cant remember what logic they put in there movies

I AM TINKER BELL'S ONLY EVER WAY BEYOND BIGGEST, HUGEST, #1 FAN EVER!!!! I ALWAYS HAVE BEEN, I ALWAYS AM AND I ALWAYS WILL BE, IN EVERYTHING AND WAY BEYOND NO MATTER WHAT, MORE THAN ANYONE/ANYTHING AND WAY BEYOND, IN THE PAST, PRESENT, FUTURE, OF ALL TIME AND WAY BEYOND!!!! I WAY BEYOND EVERYTHING DIBS, WAY BEYOND EVERYTHING BAGSY, INFINITY/INFINITE PERCENT AND WAY BEYOND!!!! I LOVE TINKER BELL WITH ALL MY HEART, EVERYTHING AND WAY BEYOND!!!! SHE IS MY LIFE, MY EVERYTHING AND WAY BEYOND!!!! IT IS WAY BEYOND IMPOSSIBLE NO MATTER WHAT TO FIND A BIGGER FAN THAN ME, IT ALWAYS HAS BEEN, ALWAYS IS AND ALWAYS WILL BE NO MATTER WHAT AND WAY BEYOND, IN EVERYTHING AND WAY BEYOND, IN THE PAST, PRESENT, FUTURE, OF ALL TIME AND WAY BEYOND!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! Maybe because they only require enough magic when a fairy is born and they are allowed to cross over only at that time.