Yes and no. If you go by the fastest routes, you will run across cashless tolls. If you're willing to take a slightly longer or slower route then you can avoid the tolls.
If you want a relatively fast option without cashless tolls, take the MacArthur Causeway from south beach to I-95 north (avoid express lanes on I-95), to I-595 west near the Fort Lauderdale airport (again, avoid express lanes on I-595) to I-75 N towards Naples. I-75 does have a $3 toll, but you can pay cash.
A slower, somewhat more scenic option is the Tamiami Trail (US 41).
Edit: avoid the above options during evening rush hours.Edited: 13 May 2018, 01:45
Avis Sunpass program is automatic, you can’t opt out of it.
Actually i rent Avis and it isnt.
there is an on/off switch inthe cars i've rented, and my last one didnt have one at all.
I know, i've read that. just giving my personal experience as I rent them frequently as I usually fly BA or One world alliance (ie AA).
That is just how it has been. Once there was a sunpass but was in the glove box not attached. It had velcro to attach and just wasnt.
I have my own sunpass now and have never been double billed so far.Edited: 13 May 2018, 06:33
Hi, thanks for replies. Looks as though I can refuse the upsell of a pass at rental counter
732gjsr - No upsell at the counter - as objets says technically you are automatically opted in to the toll program, but as amanx says you have still have a choice to switch the transponder off or on when you get in the car (assuming it is attached to the windscreen!).