According to :

If there is a flaw in this reasoning I will sure be glad
to know before I fry my relay!

It's not contactor temperature you have to worry about per-se.
It's contactor erosion.

The contacts won't make contact at exactly the same time, so,
one of them takes the brunt of the make/break arcs and erodes quicker
than the others.

Make/break arcs are what destroys non-HP-rated relays or switches
with motors.

Secondly, due to erosion, the contact area (and hence resistance)
will vary over time. A tiny difference in absolute terms will make
a _huge_ difference in current balance.

Paralleling conductors is generally simply not done _unless_ a
single conductor is in itself enough for the current flow. Paralleling
conductors then is only a means to reduce the resistance of a conductor
(voltage drop), not increasing its ampacity.

Same thing for relays where it might give you a level of redundancy, but
not much more.
--
Chris Lewis, Una confibula non set est
It's not just anyone who gets a Starship Cruiser class named after them.