I was quite pleased that they did something in this set of investigations that we've never seen GH do. And it's a particular peeve of mine ever since the Fort Mifflin and especially Fort Delaware episodes.

They actually had someone stand in a spot and then aim the Thermal at it!! And what do you know, the results were exactly what my own (somewhat cruder) experiments showed. Lack of a heat signature from foot prints is NOT an indication that "it was a ghost" The residual heat from the person's feet simply dissipates too rapidly.

See the middle part of this writeup where there is a dialog from Jason about footprints and then my rebuttal below: http://www.skepticalviewer.com/2009/03/22/fort-mifflin-steve-vs-grant/

This also applies to the episode with the hooded figure. Bare foot would be a slightly different situation but I doubt that was the case with the hooded figure running, nor the cases of Forts Mifflin and Delaware.