Waving hi. . .The Pollards apparently didn't tell the PJ of their Leicester link when they were interviewed about the sighting. . .
I don't think the parents are pulling strings to get people they may have slightly worked with (only hinted at to this point so no link may even exist) to put forth false sightings to make them look innocent.
More likely that anyone from that same area as the mccanns would feel great sympathy for them and would probably be hypervigilant in looking for missing little Madeleine. If anything they may have been oversensitive but not likely to have been trying anything sinister.
Who wouldn't like to be the hero that saves the missing little girl who was from the old home town? They probably thought they had a real sighting and probably never thought of the possible connection being important since they were not being dishonest about the sighting.
And given news reports like to sensationalize I am not yet convinced they failed to tell anything. But even if they had, as I said it would not need to be anything sinister.