Not the best souvenir to take home. But it does happen, and when it happens, it's like Freddy Krueger. Not like the original Freddy Krueger movies, but Freddy v. Jason bad.
Some people have entire rituals devoted to staying bug-free—cough—but unless you've got experience with bed bugs, it's often hard detecting them, knowing what to look for and making sure none of the creepy crawlies hitch a ride back. Even with packing and unpacking in the foyer, one missed step can wreak havoc. Bring in the experts.
Robert Macri, an actual pest control man in what I consider The Bed Bug Capital of the World (aka New York City) has some advice for travelers who suspect they may have run into the darn things. He says, in order to properly rid of traveling bed bugs, a suitcase should be thrown into a large plastic bag.
Then, it should be sprayed down with rubbing alcohol (isopropyl alcohol) distilled with some water—a spray bottle under 3 ounces will make it travel-friendly. These will suffice for those who don't have time for a DIY solution. This should be done on both the exterior and interior.
(The reason for the clear bag is that it will contain the bugs and eggs in case the luggage is infested. In which case, the bed bugs should scatter and make themselves obvious. All it takes is one pregnant female to ruin your life.)
As for going full commando, PestKilled mentions:
When dealing with bed bugs, a 91 percent solution isopropyl alcohol will give you the best results. If you can’t find this, a weaker solution is an acceptable alternative.
Clothes should also be packed in a clear plastic bag (see a theme?). But, there's another ensuing purpose here. It allows items to easily be dumped into a washer and dryer, at the highest heat setting, promptly killing any remaining critters left.
For extra protection, it never hurts to go with hard-sided luggage so bed bugs have a harder time embedding themselves in the contents.
Also, never put bags on the bed. Zero tolerance that shit!