I was also at the Goshen lecture and disagreed with the idea of caulking on the outside of the enclosure. I caulked mine along the entire inside joint when it leaked the first time we used it and it hasn't leaked since. Since HL was known to drill holes in the enclosure to attach the frame, why trap water under it? Before caulking it, I could see where HL's attempt at caulking under the frame left gaps.
JohnDar makes an excellent point here. The neo Angle shower enclosure is installed and screwed to the base. Water would potentially get into or through those drilled holes and cause future damage.
I don't disagree though, Caulking outside the enclosure is a great idea but steps need to be taken prior to doing it. Remove the entire enclosure, clean up the mess that's already there and reinstall the enclosure and caulk the perimeter from the outside. Be sure to caulk the screw holes from the factory install. I've attached pictures of my shower from several years ago. I caulked on the inside because I didn't know any better BUT, I have no leaks either.
I have also found that water can get into the frame through the rubber bead seal around the glass panel as shown in one of the pics.
AND, When installed at the factory, the vertical frame pieces that attach to the right and left sides were not radiused, making it difficult to caulk. I radiused the corners for a better fit.