inflatable sleeping pads in AT shelters...

[Dogwood]

Check for nails, splinters, staples(YEAH!), metal, glass, sharp pebbles, pointed twigs, crap stuck between floorboard joints(pens, pull tabs, wire, tin), etc first regardless of where you pick to sleep if you are intend using an inflatable pad. A groundcloth helps to protect from punctures but is no substitute for complacently not checking for these things. If you're using light wt/UL gear know what you're getting into and the TLC required preferably before you buy.

[Dogwood]

Not to worry. Throw you inflatable down wherever you want. I'll be selling patch kits and offer a fix a flat while you wait service at mile 150.

[Cuacoatchoo]

A ground sheet is generally considered good practice. As is a patch kit if you use an inflatable.

If it means any thing to you. Andy Skurka is a pretty reputable backpacking celebrity. He hiked coast to coast with a 6lb pack and even he carried a groundsheet.
http://andrewskurka.com/2014/backpac...eeping-shelter

Plenty of people including myself don't use one and it's not a big deal. If I had access to some Tyvek though I'd probably carry it.

[RockDoc]

Tent tyvek footprint ground cloth, widened by sewing on a few rows of tyvek running event bibs. Adds some color.

[Sandy of PA]

I built my rain skirt slightly bigger than my pad and use it. The draw string is long enough to allow it to lay flat and Velcro opens all the way down the front.

[CarlZ993]

I used a ground sheet for my pad in shelters (Zpacks). I was really careful with my NeoAir Xlite. Never got a leak. YMMV.

[English Stu]

I mostly avoid the shelters but was told to avoid sweeping them as the dust created is toxic from mice and funk.

[Singletrack]

I was also told by a Shelter maintainer, that they no longer put brooms in shelters, because it stirs up the dust from toxic mice poop. Best to stay in a tent.

[MuddyWaters]

Most shelters have brooms
Without sweeping them, they are really filthy.
When theres no broom, use the shelter journal to sweep.