Board Thread:Wiki-Related Discussion/@comment-25491743-20151002171811/@comment-24304025-20151203011958

There's another thing here. Emma never used dreamcatchers on Merida.

Yet she could return her memories using one.

What wiped Merida, Arthur, Violet etc. memories was the curse. The dreamcatchers were just a way for Emma to return the memories before the curse was broken. It seems pretty reasonable that, even without dreamcatchers, TLK would return everyone's memories.