According to at least one source, which is by no means comprehensive, more DNM buyers are arrested than vendors. LE doesn't seize vendor accounts for nothing.
So don't kid yourself by thinking you're safer as a buyer.
Also, the indictment against Alpha shows LE acts as buyers to investigate vendors and market operators. Read the indictment if you haven't yet.
So vendors are probably more likely to sell to a cop than to be ratted out by a legitimate buyer.
Just remember who the real enemy is among us. Keep your house clean, don't needlessly badjacket, and trust your instincts.
tl;dr all buyers are DEA agents and all vendors are DEA agents. That's why they have money and the best weed.
Can only speak for Germany, but german LE definitely cares even for small time buyers. Takes their time to get to them, but they get to them if they can. Of course not full on "we kick your door in with armed units", but the consequences DO exist.