Oh yes-not only have I seen it done, I've done it myself, many, many times! Especially in elderly men with potential urethral strictures or that enlarged prostate, it gives you plenty of lubrication to enable you to get the catheter into the bladder and cause the patient the least amount of pain.
As far as I am concerned about it "clogging the catheter," that is a bunch of hooey. It is a water-based gel, so will dissolve upon contact with urine. I have never, and I repeat never, had a problem cathing an elder gentleman using that technique.
One caution-as you hold the shaft of the *eni*up near the glans, insert the tip of the 10 cc syringe gently into the urinary meatus with the other hand (always "break" the syringe in by pressing the plunger down beforehand, until some lubricant comes from its tip). GENTLY instill the lubricant. If you feel any resistance, do not continue to press the plunger down-you could easily rupture the urethra!