It DOES kinda still work.
If you start with SitRep then change at the latest possible second, it'll show you things that were planted in that amount of time.

For example if someone plants a claymore at the very start of the match, THEN you change to your ninja class, you can continue to see the claymore they planted whilst you had SitRep on. But nothing after you've switched, so unless you're really lucky this glitch is a bit useless now.