Always test to be sure. What might come out easily on one project may not come out of the next. I wa gifted some washable markers that state they wash off from hands/ skin easily. ( might) wash out of some fabrics when washed with Hot water and strong detergent.
i prefer using ( made for marking quilts) air/ water disappearing markers. Since that's what they are made for.
Pit also seems to depend on if your fabrics were prewashed, any starch/ sizing used.... Lots of variables when using tools made for something else. So, to be on the safe side, test before marking a whole quilt.
i marked a whole quilt once, the marks came out of the top fine, but ( seeped) through to the backing and stayed there forever. I was so upset, & it was a marker a quilt shop owner talked me into.