My parallel existence is in the sales industry; I recommend, and offer for sale, various fitness products. The shameful thing, at least from a revenue-driven point of view, is that I sometimes offer simple solutions to customers' fitness quandaries that require nothing to be purchased. For instance: a lady approached me about purchasing resistance bands to perform knee extensions. In this particular case, the ankle weights currently in her possession were already a worthy element for this purpose; therefore, she purchased nothing.
I have also implemented something else free of charge in my Spinning® classes as of late -- something that is so simple and yet offers a tremendously useful training outcome. In the interest of increasing my attendees' ability to train outdoors in Southern California, and to a wider extent being relevant for summer weather virtually anywhere, I have turned off the fans for as much of class as they will allow. Basically, unless I hear obvious complaining, I leave them off.
My rationale, in addition to being purely motivated by heat acclimatization gains for attendees, is that we often speak of the Spinning® program as being drawn from road cycling; in fact, it remains one of our core values. I would contend that if fans are blowing at RPMs several times our cadence value (anecdotal estimate), how are we in alignment with road cycling? (I have issues with fans on treadmills for a similar reason.)
Now for another perspective: we do serve general population. That means that everyone should feel welcome in Spinning® classes, yes? Yes! Most emphatically! For someone who has had little to no exposure to Spinning® classes or other cardiovascular modalities, the idea of leaving the fans off is quite unrealistic, unsafe, and perhaps even cruel.
However, if a participant can bear it, I say to bring it (within reason and within the given objective(s) of the ride). There is no reason, then, why fans should be automatic, unless it is some sort of facility rule; or unless the population present indicates the use of fans.
One last thing before I close: we also speak of the 40 for 40 rule, which is simply a guideline stating that we recommend an ounce of water intake per minute of training. Devoid of fans, I would say that our hands are effectively forced in the matter of hydration.
It would seem that we fool ourselves in regard to our true fitness level if we are able to train without fans, even as we elect not to do so.