The safety issue seems hard to take in light of all the pnuematic appliances out there, And considering all the car tires that are going around. 

 The moisture issue is something to consider but with the small amount of air were talking about I don't think it's a problem.

  Glad to hear both sides of this, and if this was a new tractor i would stick with the dealer rec..Tractor will probably outlast most of us no matter what you put in it.

  Well I will give you the cheap part since I have no good rebuttal for that.=(:)

 As for the dangers, with the small amount of air we are talking about in this situation I don't belive it would be near the hazard of such things as air brakes with compressor oil that gets mixed and pressurized through the system or the air over hydraulic's that run everything from jacks to car lifts to cylinders in the industrial world.  Add the thousands of miles of oil pipelines with air bound to be stuck in there somewhere.

  In this case if oil is coming out of the schrader valve it means the seal is shot anyway and no amount of air will keep it up. If no oil is coming out then the two won't mix anyway.

    In the end it's whatever you ar comfortable with.

There is an ENORMOUS difference between putting oil in a high pressure O2 environment and putting air at low pressure in an accumulator.  Surely you are experienced enough to know that an accumulator is basically a hydraulic cylinder with oil on one side and gas on the other, and that under normal conditions the two sides are completely separate.    Surely you are also experienced enough to know that we put air and hydraulic oil in the same space and pressurize them together every time we hook up a cylinder which has been moved with a fitting open.   I haven't heard of any cylinders blowing up when you first cycle them, have you? 

Sometimes one must make a distinction between what is theoretically possible and what is  plausible.