Find my iPhone giving wrong location for airpods then wrong location appears different the next day?

Had some random stranger show up at my house at 11:30pm asking if I had his airpods because he lost them 5 days earlier and they're pinging to my backyard. Helped him search, got irritated after 30 min and he said he'd come back the next day. Today he comes back and says they're not pinging to my front pasture about 1/4 a mile from the location last night. Again, trying to be nice helped him search then he accuses my son of taking them and tells him that he's called the "apple police". How could this happen? Also, 5 days after losing them how could they still do anything? He said on his Find my iPhone app it shows his airpods as "gray". What does the gray color mean and how long will they ping after the battery is dead? Had to call police to get him to leave.