Don't come whining to us about a flat if you aren't using sealant. We'll just laugh and point.
Running Hutchinson Protect'Air Tubeless Sealant in your UST or ghetto tubeless tires won't make you invincible to flats, but going without it is just plain stupid. Properly applied, Protect'Air Sealant self-seals punctures up to 3mm wide, and one application lasts for a full two years inside your tires. It's inexpensive, weighs next to nothing, and takes zero effort to use. In our opinion that's a fair trade for 15 minutes spent trailside, unseating a tubeless 2.5 in 100-degree heat to find a hole, patch it, and let it dry.
I have had great luck with Protect'Air Tubeless Sealan. It has fixed many a flat from goat heads. I found if you put your finger over the hole it helps seal it faster. Holes about the size of a pencil you won't be able to seal though. I prefer this over stans, seems to last longer and seal faster.