In short, the game will now automatically toggle a sponsors sponsorship off when a new player has done the jobs for their crew but goes uncontacted.

This does not remove the player's ability to be a sponsor, in fact the player only has to click the "Sponsor: Off" link at the top of their page to toggle it back on. The details are as follows:

For a worker to to be considered contacted, one of the following must happen within 30 minutes of the last time they complete a job for your crew:

• A sponsor clicks the "Click to contact..." link.
• A sponsor clicks "Hide jobs and mark as Do Not Contact for this worker." 
• The worker joins a different crew.
• The worker dies.

The sponsor must have been active when the worker did at least one of the crews jobs as well as during the 30 minutes after the last job.

The purpose behind this change is so that those who are absent minded and do not toggle their sponsorship off when they are unable to fulfill their sponsorship duties do not cost their crews more cash than necessary and also to ensure that new players receive a quick response to their efforts working for your crew.