I've successfully glued tieouts on my silnylon tarp. The tieout loop was sewn to 5x5 cm square of silnylon and then glued onto the tarp used silicone sealant (not diluted). I used pea-sized bead of the sealant, spread evenly on the patch using my fingers. After placing the patch on the fabrics, I carefully pressed out all air bubbles, put a load of heavy books on top of it (separated by PE bag) and let it cure overnight.
I didn't needed these tieouts in field yet, but I did some tests before I used this method on my tarp. In case of tieout stitched in the middle of the patch, the tieout will tear from it before the patch will be torn off. I've also tried to peel of a glued patch from side, where it was not glued. It is possible but it requires surprising effort.
I hope it will work well on my tarp. If you're not sure about this method, try it on some scraps beforehand.