All airlines have an address on file for each of their pilots, as well as contact phone numbers. The only way I can see that this could have developed, is if the pilots in question have a 'crash pad' close to the airport for reserve duties & the like.
If that is the case, it would appear that the company has suddenly taken exception to a situation that has been going on for years & decided to take the stance that the crash pad is the pilots actual address.
It would appear that it is either a zealous management type trying to earn brownie points or, as has been suggested, a shot across the bows to signal the commencement of a new, hard line industrial policy from management.