In my experience, most Russian border officials don't even speak English, and will rarely ask EU citizens a single question about their trip.

That said, to get a tourist visa you have to get a letter of invitation (LOI) either through a hotel or an agency selling LOI:s. Many LOI agencies don't require you to book a hotel with them, but do **not** tell them you're staying at a friend's.

You won't get your LOI back after sending it to the embassy, and at the border you're only expected to present your visa and (if entering by land) filled-out migration card.

That said, technically what you seek to do is illegal, and if somehow caught (for example if hanging with your friend and stopped by the police, they'll see your friend is Russian and could investigate whether you're staying with them), your friend may actually be in bigger trouble than you, as it is **a criminal offence** for a Russian (or resident foreigner) to host a foreigner without permission to do so (in the shape of a private LOI, to be obtained through the Russian Federal Migration Service).