The "someone" was a couple of pipemakers. I would give credence to what they say, and add that I have no problem at all with soaking a pipe in water if a circumstance calls for it. I have had the time my girlfriend (now wife) washed my pipe in the sink like it was one of the dishes. I occasionally drop one in the hot tub. And, I have gone to bed leaving a pipe or two on the back deck and they've spent a balmy evening getting rained on, with not a single one harmed in any way.
Now, just immersing a pipe in brandy to clean it, while not exactly going to damage the pipe, just isn't an effective way to clean one, IMO, unless the pipe has some sort of nicotine patina on the finish that you want to remove. But, it's just quicker and easier to dip a pipecleaner in some rum and ream the draft.
I cannot attest to what sable says about silicates, myself. It sounds plausible. And, I would maybe avoid keeping my pipes soaked in alcohol for any extended time. But, I don't think an occasional bath is going to penetrate into the briar with any significance. IMO.
It has been said time and time again, most of what pipe guys believe about these seemingly magical things is mostly just bunk superstition.
While I see no need to soak a pipe often for my own, I am also not going to loosen my bowels if someone else does.