This is shakeweight and i'd like to clear some things up.
Anyways, i "stare" at "walls" (when in reality i stare at corners) on maps like office and wait for sound/radar and then i peek. For example, this is the best way to hold long hall on office. You wait on the back right until you hear footsteps, nades/flashes or get a radar hit and then strafe out and/or flash. There's tons of other example i could give, like holding your crosshairs on the corner of a wall when you're covering short-A as a CT. Then you can just wait for sound/radar and peak with your aim already alined. Playing smart doesn't make someone a hacker.
Also, having my crosshairs on someones head when i turn a corner doesn't mean i wall. It means i have good map-sense and know the key camping spots. Anyone that's halfway decent at this game realizes this concept. While i'm on the subject of map-sense, prefiring into these keyspots (ie, you peek and fire and then retreat without actually knowing if someone is there) doesn't mean someone hacks either. If they do it consistently then i'd agree that something is pretty fishy, but prefiring certain spots based on rush-timing is completely natural. To give you an example, if you rush market as T on italy, prefiring the ct-sided-entry-point into market will almost ALWAYS result in a kill if you have good timing. This doesn't mean someone hacks.
Another thing that some people suspect as "hacking" is when a good player is running, they won't hold their crosshair on the corner of a wall, instead they will hold their crosshair about one-crosshair-width to the inside of the corner to compensate for movement. So if someone does peak you can just move your model (ie. use A and D) to line up a shot rather than actually having to move the crosshair. People see your crosshair on the wall and just think "lol this guy is walling," when in reality it's just playing smart.
To a mediocre player, these things look suspicious, but to anyone that's been playing for a long time, they're just tell-tale signs of a player with good mechanics.
edit: and i never left when i suspected you were going to voteban me, i never even thought you were going to voteban me so now you're just being paranoid and silly.