Often times throughout the course of a year, users will be outbid by $1 by their commissioner. If it happens on more than one occasion, it's understanding to suspect some sort of cheating or peeking.
There is currently one way in which a commissioner can see anyone's bids at any time. That is by them going into the Member Settings, temporarily un-assigning a user from a team, and assigning themselves.
These actions will automatically trigger a league chat message to show which teams they have gone into. So if you are skeptical and you see those league chat alerts, then you have a good idea that they looked.
We will continue to identify ways to disallow this even further.
If you have any questions about this, please email support@sleeper.app.