If there is visible mold, there is also plenty of invisible mold and more importantly spores...I wouldn't go so far as to say that visible mold is harmless because of this...it's a good indicator that there is a serious problem in your snakes cage that needs attention when you can actually see mold growing.
Now then...to go so far as to try and battle any little microscopic organism that dares venturing within 20 feet of your snake's cage is just not healthy for either of you. You will go nuts...and your snake needs a little tiny bit of nasty now and then to keep his immune system on guard and active. Let down the defenses and down comes the castle walls.
nonbacterial RI is probably a secondary condition brought on by lowered immune system from some other issue that allowed the otherwise benign pathogens to overcome and rear their ugly little heads. With boids that's usually cage temp issues. Healthy well kept snakes are far less likely to allow the bugs to bug them....take that same healthy snake though and drop the temps a bit and the bugs take over. (for instance...never ever ever never ever ever ever ever let a boa go at or below 70 degrees for more than a few minutes)
But anyway...I guess what I am saying...is if you understand what antibiotics do and how they work...and also understand how natural antibodies work and how they can sometimes work together or inadvertantly against each other especially when used incorrectly...you will understand how over medicating and over sterilization can sometimes lead to bigger problems down the road. I am not saying don't clean your cages...nasty cages are a far bigger problem than cages kept too spotless. The main point is to correct husbandry and give the animals natural defenses a shot at it before pumping them fulla bugjuice...push fluids and keep em toasty warm...it will usually go away on it's own. But somehow even as hard as I push this....I still manage to go through a few full viles of baytril and other various drugs a year so I'm not one of these anti-doctor people...there is a time and place for any and everything.