Enabling Manual Intercept will stop new leads from automatically routing.
When a new lead comes in, it will be held in a paused state. The administrator will be able to preview who the lead may be offered to at this time by clicking on the lead and viewing the lead routing details from the sidebar.
This is a valuable tool during the implementation stage when first configuring the account. Once the routing rules have been set up, it is recommended to turn this feature off to ensure leads are acknowledged as they come in.