Perhaps a fire hazard.

Have I mentioned that my family is going to visit soon? Have I? Have I?

Yes, of course.

Today, my parents' bed arrived in the mail. (Because the college's expensive guest rooms are (all but one) twin-bedded, I decided to go my own way, knowing that my parents would prefer to be in a bed together than in two beds side by side.) "Do you think you can lift that?" the porter said when I checked my mail and found that I had a package waiting. A double-high double-sized Aerobed™ weighs more than you'd imagine. But as you know, I am nothing if not strong and stalwart, and so I crouched down, lifted with my legs, and hauled that thing back to my room.

Where, several hours later, I cleared everything out of the way so that I could test it out. Turns out they're not lying! It really is as high as (if not a little higher than) my regular bed, and it's easily as comfortable. And it has "stabilizer bars" on either side of the bottom of the bottom mattress, presumably so that if you roll around too vigorously in the night, you don't flip the whole thing over.

Once it was inflated in my room, there was basically no floorspace left (a situation I can rectify in the future simply by doing a bit more rearrangement before inflation). I thought back to the fire safety code we had to follow in college: no more than 50% of the walls covered in posters, for instance. Strangely, I don't remember there having been a rule about the maximum amount of floorspace one could cover with beds.