I will probably get flamed for this but I do not think your points should be refunded if you don’t have any evidence that you didn’t bring them in. Not discovering it until you got home would give me pause. Since they are offering to treat your home, that is more than enough.
I do inspections of affordable housing and we do check for bedbugs. They are very common. On days that I am in the field I get undressed in the garage. We do have spray that we apply to our clothes prior to an inspection but it is not effective. Our office gets a report of a bed bug being found at least once a month. Which to me is pretty low considering we have 40 people going in other people’s homes about 20 times a day, each. The dogs come in and sniff for more and we always have human scented traps around to try and catch ones that aren’t found. I say all of this to point out that although I work in a cautious environment and I am cautious, it doesn’t mean that I haven’t brought one in somewhere. In my line of work though they are so common place to us that it is no different than a mosquito or rat infestation. We know both of these are at WDW and should assume bed bugs are too. Hopefully a rat will never hitch its way home!
All of this being said, we do look for them as soon as we get in a room. Always put our luggage on a hardgood, wash clothing before we leave for home, unload them in the garage, place empty luggage in a garbage bag and leave in the hot garage for several weeks, then take to basement. Take the clothes and put in the dryer, then wash them again. Be sure to check all stuffies like you would check your dog for ticks and be sure to wash them also.
And after all of this work I usually say to myself, “why do I try so hard they are everywhere anyways?!”