The actress showed up Friday in Washington, D.C. and -- like she has week after week -- she urged Congress to act on climate change. Then she started marching with other protesters, and this is usually when police step in and issue 3 warnings ... before taking Jane and others into custody.

But, it never happened. Jane simply got into a waiting SUV and bounced.

Why? Sources with direct knowledge tell us ... protest organizers urged Jane not to get arrested for what would have been her 5th time in as many weeks because she risked more than a month in jail. Jane currently has an open court date later this month, stemming from her third arrest, and because of that she could have faced 30 to 90 days behind bars.

We're told the "Fire Drill Fridays" folks made it clear to Jane she was more valuable to the them leading the weekly protest -- drawing a spotlight to the cause -- than she would be rotting in a jail cell.

Ben & Jerry's cofounders Ben Cohen and Jerry Greenfield also joined Jane. So far, they have avoided getting hauled away. We're told the police appear to be giving everyone a pass this week because the dozens of weekly arrests just become a nuisance for law enforcement.

To that point, Ben and Jerry definitely charmed at least one Secret Service agent on the scene with their weapon of choice ... a cup of their world famous ice cream. Brilliant move.

As we've reported here, here, here and here ... the protests were inspired by Swedish teen activist Greta Thunberg. Jane's 4th arrest last week meant she had to spend a night in jail.

Celebrities alike have joined Jane at the nation's capital and see the arrest as a badge of honor. Jerry told us earlier this week on "TMZ Live" it didn't take much pressure from Jane to join her on the frontlines.

As you probably know by now ... Ben & Jerry's have been calling for climate change action for YEARS now. They even launched a Save Our Swirled flavor to shine a spotlight on saving the planet.