I usually try to judge based more on how they play rather than what they use.
Betties... I get "free headshots" on snipers ALL DAY LONG because of those things. Duck, boom, sprint, PLINK!
Target finder... yeah, please don't use that stupid thing. I'm half color blind and I can use the other reticles (unless they're red/orange) just fine. I tried the target finder once... 14 and 1 (back when my aim was consistently bullcrap because this is my first "major" fps... I own it and play it regularly whereas prior to this it was a buddy handed me his controller and let me play on COD or whatever for a bit... and ruin his scores. lol)
Shock charges... mmmmm... yes, they're cheap... but easily countered and half the time the guy isn't near the thing and I walk away scott free. (or sprint as the case may be because I don't wanna stick around to find out if he IS there. XD)
I personally find claymores more annoying. NO warning if placed appropriately, OHKO (save for flak jacket which I rarely run seeing as MOST explosives are fairly easy to escape). --- Made of Earth, Formed of Water, Kilned in Fire, and Sings with the Wind. Ocarinas are Born of the World and Loved by the World. PSN: Gregory_H64735