Would it be possible to charge citizens in debt for stabling horses?

About a thousand times now, I have went to the drawbridge at the keep, waited, went to the stable, took everything off my horse only to realize that I don't have the coin on me to stable him. so now its back out to drawbridge...blah blah

If Srela will heal me up and charge it to my account, why can't the stablemasters? Heck, they know me better than Srela does.

Thanks,
Canaw, Advocate of Sir Beren