Having worked at a fast food join (not McDonalds) much earlier in my life, any lacking maintenance and proper cleaning, especially if there has been a power outage will turn the the machine into a rapid incubator for bacteria that will make you ill.
Since shifts change and not everyone keeps on the machine, a power outrage can quickly be lost to the workers.
Getting angry if an employee tells you the machine is broken and demanding ice-cream is an exceedingly bad idea. Take that as a blessing. The employee may have saved you from running to the bathroom a lot.
I personally stay away from softicecream entirely. But if you must, try to find a place where a lot of people are buying so the machine is in frequent use. That doesn't mean its safe but it makes it a lot more likely.
Of course not being used frequently is not an automatic reason for the machine to be in incubator mode, it may will be well cared for, well cleaned, great maintenance.