I think the biggest issue is size. PSK stands for Pocket Survival Kit. The most common container is an Altoids tin or similar sized container (bandaid box, cigarette box, etc.) <br><br>It would be difficult to fit any size tarp into a container that size. Shelter is one of the big three, water, shelter, fire. Carrying a shelter is preferred but is beyond the scope of a PSK. If you move up to a larger container- fanny pack, daypack, etc., carrying a shelter is a very realistic opportunity.