Using a #sponsored #ad disclosure is not always necessary as long as there is a specific hashtag that discloses an influencer-partner relationship, such as #[yourbrandname]insider. However, as Mavrck is a platform, you as the brand have the ultimate decision power for how conservative you'd like to be. If there are any concerns, then #sponsored is what should be used.
The goal is to avoid anything that’s deceptive and that a majority of audiences wouldn’t understand as disclosing a sponsored relationship, which is why #spon is explicitly not allowed, as an example.