They've done this kind of thing on occasion before o.O.
They briefly experimented this until the Archer's ring fiasco, after which they shut it down (there was even an official post from Jagex on Reddit which confirmed they were suspending the refund plan). Afterwards, they went back to ignoring and not acknowledging these server disruptions issues, meanwhile giving famous players refunds when they needed them.
So this is indeed a change and a reversal in their policy.
Can you give any proof that they only reimbursed famous players for their losses during that brief time? Who were these famous players, and how do you know no one else got reimbursed in the case of server side malfunctions/hacks?
Sure. If you'd like a famous case of Jagex refunding a prominent player's item, just consider the case of Dragonseance. It was discussed even on TIF (specifically in the 200M thread), and various other places and is very well known. Basically someone hacked his file, and because he didn't have the good sense to have a bank pin, they were easily able to take his multi-billion GP bank, and they changed his name too. Not only did Jagex reverse the name change, but they also refunded him most of his items (except for Silverhawk feathers I believe). I can tell you for a fact that if it had been anyone else, Jagex would have told them, "Sorry, it's your own fault for not having a bank pin." But because it was Dragonseance, someone who happens to be one of the top players in the game, they looked the other way. In fact, in previous years many people who got hacked were told to take better care of their account security.
As for cases of people who didn't get refunds, they are very common ad I have written about them in the past on TIF. In late December 2013 and early January 2014, as well June 2014, there were server disruptions in which lots of worlds went down due to various reasons and quite a lot of people lost stuff. Naturally they went to post on RSOF, and a lot of the forums were litered with posts asking Jagex for item refunds or rollbacks. What did Jagex do? First, they refused to acknowledge that were server disruptions, they were quiet about the whole thing for several hours. They instructed forum moderators to lock all threads on the subject, hide posts in cases, and warn people that if they did this again they'd be punished. And that's exactly what happened all 3 times. One time one J Mod did get on an alt account though to make a post (which was stickied by forum moderators) that stated there would not be any rollbacks under any circumstances. Sometime later they sent Mod Tyran or whoever to make a post briefly acknowledging that there were server disruptions but nothing was ever done to address the dozens of complaints sent. Nothing. I also know people who have contacted Jagex on this matter and been ignored. So there's plenty of evidence.
They've reimbursed for a very very long time now, provided that you had proof (eg. video/livestream footage) that it was a server issue. This is likely the reason that "only famous people" were, because they're often always recording or streaming while they PvM/PvP.
This is not true. Jagex's refund policy has nothing to do with their being a supposed lack of evidence in most player's cases. Saradomin Mage posted a screenshot earlier this year of a J Mod post on RSOF - I think OSRS it was, where someone was complaining about how he had lost a particular item and he didn't know where it went, he thought it might have been eaten by a glitch. The J Mod responded with a *very* detailed log that described his ingame actions almost every couple of seconds and he told the player that he had dropped the item at such and such time (probably accidentally), but in any case he wouldn't be getting a refund because that wasn't Jagex's fault.
So they keep detailed logs on in-game stuff - very detailed logs, and they can certainly tell if someone has lost items or their technology is very close to that. They have the technology for this and have had it for quite some time. They simply refused to do anything about it until now.