Movement and Forced Marches

I've got two PCs who scouted ahead of their main force some distance *on foot*, using almost half of their movement getting to their target (an ogre village) and noting that the ogres are retreating (due to heavy losses they previously suffered at the PCs hands).  Anyway, they are contemplating returning to the main party to warn them so that everyone can join in pursuit to salvage the sweet, sweet loot the ogres are carrying with them.  

My question is this: given that going there and back, on foot, used up most of their movement for the day, and that their mounts are back at the main camp, would you allow them to saddle up and ride with the rest of the party (ignoring their used up movement and effectively starting over with their horses' movement allowance) without considering that a forced march, or is any movement beyond their allowance (even if they aren't actually doing the work) counting towards a forced march?

I would definitely count it as a forced march. 

(Riding a horse is almost as tiring as walking, for what it's worth. It's just faster and you can carry more.)


As I understand it, take the miles per day number, divide by 8. This is the miles per hour number. Count up the hours with each form of transportation. If this is above 8, it’s a forced march. 12 hours is the official upper limit.