I could see it as being a part of some internal identification system they use. To keep track of pets, urns, or what is being worked on a particular day. Maybe which urns have been reserved and which are free to use.
What I think may have happened
Someone cut the stickers and left it on top of whatever they were supposed to identify, for someone else to use later
It was never used or needed, and fell in with the stuff that was sent to you
Best way to confirm would be to ask, I'm sure they wouldn't mind confirming!
If you stick it to something and then peel it off, does it leave a symbol? They have tamper detection stickers that leave a design when peeled off but they may not have used it on yours as it appears to be a fabric.