Hey anybody remember Olivia Newton John?
Let's get technical, technical, I wanna get technical, technical...:))
Isn't radiant heat loss a reality with darker coloured fabrics, due to the fact that the emissivity climbs towards 1.0 as the material becomes "blacker"? i.e Black materials are more transparent to infra-red than visible light is?
Based on this sketchy remembrance of thermal physics, I think that perhaps a mattress such as the BA IAC could indeed benefit from a little reflective mylar (space blanket or Reflectix), especially since it's black.
Over to you Richard N.!