Yes you have to. Running a trampoline park without insurance would be extremely risky.  All businesses, no matter in which industry, are facing potential risks that should be covered by insurance. 

You probably have a lot of money and time invested in your trampoline park business, but maybe only one accident in your business, no matter it's not fault or not,  will cost your significant financial loss or even worse, force you to close the door. So you need the insurance to defend your interests and protect your assets if a claim or a lawsuit is filed against your business.

Related reading:

Do You Have to Buy Insurance for Your Trampoline Park?

How to Ensure Trampoline Park Safety or Prevent Injuries?