Here are the possible actions and outcomes:
1) Don't call - no violations. Result, nothing bad happens
2) Don't call - yes violations. Result, fines multiply and could lead to very bad things.
3) Call - no violations. Result, nothing bad happens.
4) Call - yes violations. Result, tolls are paid. End of bad things.
There you go. This is decision making 101. Choose wisely and go with the best risk reward scenario. To be clear, #1 and #3 cancel each other out and are harmless. Now you only need to focus on #2 and #4. Seeing as #4 yields the best outcome between those, your decision is super easy.
And to add to what someone wrote above. If you buy a $10.00 RFID Sunpass at the convenience store on the way in, they'll apply a $10.00 credit to your account so the tag ends up being free.