This topic was discussed earlier in CiteHR quite a few times—here's the link to one of them:
https://www.citehr.com/340976-increm...signation.html. You can use the research facility at the top of this page to see more threads on this topic.
I think the core essence of a salary hike is 'performance' (both in terms of job-related work and attitudinal issues) for a particular period of time—not whether the employee is close to the management or not.
For the issue under consideration, the hike is being given with effect from 1st August 2012 for the performance of the past year—during which he was very much present (and I presume performed very well, else a 35% hike wouldn't be considered).
Coming to the reasons that many employees give—'personal reasons'—let's not be naive. Unless an employee is able to share the reasons (at least partially, if not fully) at least in confidence with his/her boss and/or peers (if not with HR), one can safely assume that it's for another job. Fortunately or unfortunately, this is one reason that's highly used and misused often.
If someone really has personal reasons, his/her most likely response ought to be to ask for leave—maybe for a long duration. Would you resign when you have a personal reason and things to handle on priority on the personal front—in the process adding to whatever stress you are undergoing? Please give this a thought.
At the end of the day, like Pon mentioned, it's the 'discretion of management'—which again depends on what 'their' perceptions/views of 'people management' are.
All the best.
Regards,
TS