If you don't flag the cheaters you catch, what's the point of doing this at all. What are we changing?
Actually posting all the evidence and asking DT flag is also a pretty good course of action.
OP has posted some, Awaklara added even more evidence and now the cheaters are painted in red.
I've stopped tagging accounts, since last month's incident. but if I'm allowed to tag them, then I can do it.
I don't know about "last month's incident", but you should keep in mind some important things:
1. Since you're only Full Member, it sometimes can be a bit "risky" (may need a better choice of word here) for you tag others, since retaliatory feedback do happen.
2. Since you're not DT many may ignore your tag.
3. If you are certain about somebody, I don't see any really good reason not to tag him. And yes, errors can happen, we are humans. In such case apologize and move on.
4. If you get have many busted scammers/cheater and you've tagged them it may get you faster into DT (just a hunch).