My old company offered ALS services [RN, RT, or RN and RT trips were considered ALS]. Out of all the ALS transports I did, I transported a whopping 2 code 3 over 2 years. One was a patient who was paced [implanted pacemaker failed in the AM. He had a transvenious pacemaker put in and was being transfered to have surgery to fix/replace his implanted one] and the transferring hospital had done just about everything to screw up the transvenous pacer [they had it turned all the way up to maintain capture]. While we were prepping the patient [RN getting information, getting the patient hooked up to our monitor, etc], the hospital's RN ended up bumping the pace maker wiring causing it to come unplugged.
The second was an RT transport for a possible leaking trach. We got about halfway to the original destination when the RT noticed that the destination was changed in the RN notes. As we were getting off the freeway to call the transferring SNF, the patient desated. Of course, the EMT in the back with the RT "didn't feel comfortable" bagging the patient if he needed to.