Tube Monoblock location? - Rack or near speakers?

It seems odd that they would want the tubes vibrating.All tubes are microphonic.They(the tubes) might even get more microphonic with all the vibration rattling their insides possibly causing a premature failure. Then a longer run of interconnects too.Longer speaker cables have always been preferred over longer IC's.Its a new one to me.

 
Wrt the Sanders and Walker observations - these are not mutually exclusive.

Put each monoblock near its speaker and cable accordingly. Generally, shorter speaker cables are preferred assuming your preamp has enough output voltage to drive the needed length of IC.

You'll get different opinions here, but just take a look at pictures from CES or most dealer showrooms if you doubt placing amps near speakers. Or ask a few amp manufacturers - you'll be hard pressed to find many (any?) who advocate long speaker cables.

Of course the cables themselves have an impact. Cable geometries influence capacitance and inductance. A cable with, for example, high capacitance will smear a signal more over a long run. Keep overall reactance on the low side without disproportionate weighting of one over the other.
 

Don't forget,it is a show.Less than ideal conditions for setting up,transporting,etc.Dealers don't have the best options either.Plus audiophiles like to look at what they're buying.Those big amps are heavy too.Dealers I know keep their amps away from their speakers at home.Just another of my 2¢

I figured there would be a split in opinions here.

Blue Jeans cable for instance admit that if you are using speaker runs of less than 10 ft, just use decent oxygen free copper because there is no measured difference compared to very short cable. I think you would need better rca cables at that length which are more susceptible to interference and noise.

This is one advantage of balanced cables. The shorter you can keep the speaker cables, the better (more resolution, more impact). Preamps that have a low output impedance can drive longer cables, so some single ended preamps will allow up to 20 feet (although that is rare). For the most part, running longer cables than that is best done with balanced lines. My cables at home are 35 feet.

Vibration in the tubes is generally **not** a problem!