Had an unusual (to say the least) boarding experience at LAS on Monday evening.

Arrived at the gate shortly before boarding commenced, the first boarding call was for Group 6. Went forward with group 1 boarding cards to be told that 'boarding is from the back on instruction from the captain'.
We assumed, therefore, that once group 6 had boarded it would revert to normal 1,2,3 etc but no - boarding calls were 6,5,4,3,2,1!

Door 1L was in use for boarding and as we were row 1 it didn't really cause us any inconvenience but any Gold/Silver travelling in WT must have been quite upset about this.

I quizzed one of the cabin crew and he was unaware of this and said that "it hadn't come from the flight deck".

Any thoughts, or similar experiences?