As a former Crew Member in another department, I am aware that signing these items is a volunteer service the characters are providing. This is often done on their rest time between meet and greet sessions. While there is little excuse for lost markers, one can't even be sure if they were lost in the Guest Services/transport process of if this happened during the signing.
Items are obviously signed by one character and passed to the next. It truly is based on which characters are available to participate at any given time. If Pluto needs a dog biscuit or a walk in the grass, he might not be available to sign an item.
The CMs really do try to meet guest expectations, and succeed most of the time. Please be aware that they have chosen to give up their "free time" to provide this service to the guests. If there is truly a problem, by all means report it--that's how they improve service.
But if it is "item 2 wasn't as pretty as item 1," remember that they might have been done at different times or that the characters may have had other things to take care of. The alternative might be to charge for this service and have them do it "on the clock," or to eliminate the practice totally.
Ex Techie
(with help from another lovely DISboard member to help me put my thought's and sentiment in a more eloquent way!)