These were being sold at the 2011 NW Quilters Expo....there ARE some things to consider. One thought --we live in an area where the temps drop to 20 below at night --- would not be far-fetched to believe the quilt I'm sending out just might be left in the PO overnight --- therefore -- my quilts MAY be in a "freezer"
More than one sales booth had these pens and all of them said the same thing:
1) the ink does NOT go into the fabric --- it "floats" on top. So no worry there.
2) if you don't wash the quilt after it's finished (like my customer quilts aren't washed by me) then use a steamer and steam the ink off. They ALL assured me the ink would not show up later on. They were ALL emphatic that just ironing will not guarantee the ink disappears forever.
Note: I haven't tried it yet ----- don't blame me if anything goes wrong, I'm just the messenger