As I said, Rudy is doing it because he is the last dented can of beans on the shelf, an obscure brand in a foreign language, label faded, can starting to rust and past its sell by date. Marcone has all the beans he needs, a warehouse full, respected brands and an sell by date years in the future.
Rudy is Hobson’s Choice, which I think why he is now working for the Merlin faction to dig dirt on Harry. Even the Black Council have more nous than to employ Rudy, he is ineffective and the Fomor don’t care about mortal authorities. Getting Harry into trouble with the mortal authorities is a very Merlin move, designed to get evidence on Harry’s expulsion, AND find out what he did with Nicky which worked out so badly for Nicky.
Harry must have been very difficult to spy on magically, the Swartalves has good security countermeasures, and the wizard who tried to use magic to spy on Harry at the Carpenter House still smells colours and tastes music. Fortunately he (mostly) regained control over his bowels.
Again I don’t think it is Malvora, Lara would have been on the lookout for that, and it requires someone to know where to look into Harry’s recent past, i.e. Nicky’s worst day in two millennia to point Rudy at the problem, not sure the Malvora would be interested especially in this but the White Council would, Nicky was a former member of the Accords, who quit following events of Small Favour which involved Senior Wardens.