I tried that with the toilet one, got a grenade as a present, so it didn't work, maybe if I am in the toilet and they are near but un-alerted they may be disgusted and run off? Not been in that situation yet though.
Anyone wanting to try the Lullabye tape out it is in the storage area across from the cell where you rescue the bionics scientist early in the game, once I used it I found it in the same place again.
Also the enemy get wise to your tactics, say you always infiltrate at night they will be more likely to use torches or have nvg, and if you always use headshots they will be more likely to get helmets, you can counteract this with combat deployment once you unlock it, by sending troops out on missions to sabotage enemy equipment supplies, this can include things like nvg or even weapon types such as machine guns.
Another tip that isn't exactly explained is that if you destroy the big radars in enemy bases with explosives. you can then use them as hot landing zones. great for completing some side ops quicker.
Another thing i found is that you can choose a song from the cassettes for your helicopter to play when you are deploying or evacuating, pretty sweet to be in a epic gun fight when suddenly you hear 'Ride of the valkyries' from the distance coming in to pick you up.
Lastly you can place any posters you find onto the cardboard boxes by pressing X when selecting them, soldier ones make the other soldiers salute and there are ones of women too.