About the taped tie out attachments pulling free: How about making a "button" from a stiffer material to place on one side and wrapping the cord around it? A piece of balloon material should stop any slipping. Stitching can become a perforation line begging "tear here." The button approach might distribute pulling forces without adding a hole to your material.
I use old foam ear plugs as buttons to wrap elastic cord for my side pull outs on a mylar blanket slung under my hammocks as wind/rain/cold barriers. Works well for me and lasts for years. These are also moveable, if desired.
Best of Luck!