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