BA,
The only way that they could have got the drop on you if you were quiet and motionless is 1) if they knew you were there or 2) if they were using the red diamond hack. The first reason I could see but if the server you are playing on does not have the anti cheat feature turned on then you are at a disadvantage from the start.
Of course the third reason he might get the drop on you might be his ping to the server is a lot faster then yours. OVer all...I have not had a problem with "quiet" tactics. SInce this patch has come out it seems that the game has blossumed towards these quiet tactics. THe CS:S type of game player that likes to run and gun will find themselves getting frustrated in a hurry in this game.
Tip: concerning you being still and waiting for them to round the corner. If you are standing or crouching you have a greater chance of getting hit verses you laying prone on the floor. the 1.16 patch seems to have fixed your ability to aim low with your reticle while in the prone position. The only disadavtage to laying in wait, prone on the ground is that if you miss your enemy's head when they round the corner...you have just become a sitting duck due to it being hard to move quickly in the pron position.
Tactic Tip: In Death match mode, try to get the most kills the quickest. If you and one other are the ony one left, everyone else having been eliminated via max death feature, if you have the most kills then you are in a position to sit still and wait for your enemy to come to you. The only time tacticly I can see some one camping in DM mode is in this situation. The second person left who does not have the most kills has to come looking for you because kill totals or elimination are the only way he can win. So when they come looking you will be there waiting. Note: when they get frustrated and call you a camper, politley remind them that you had the lead on kills and had no need to hunt...LOL. Tehy will get over their frustraition as soon as they get the chance to be in the lead wityh only one left in the match. =)
Happy hunting!!