By enabling the hide low tier events checkbox, most value- and sure bets low tier leagues and tournaments will be hidden from the Bets-view. This is a filter specific option, which means that it is only applied for a specific filter (if you use multiple filters).
Enabling this option will decrease the number of bets significantly, as most smaller leagues will not be shown, but might help you stay under the bookmaker’s radar longer. The default setting is to show low tier events.
Tennis tournaments will always show, even lower tiers.
Note that a small number low tier leagues might still show even when this setting is active due to different names and format across bookmakers.