A good RTC might be temperature compensated, but most of the cheap ones aren't. (Unless you mean what I describe next...?)
In any case, what you say is questionable because the quartz crystals designed for use in clocks and watches are engineered to have an almost-flat temperature coefficient curve in the room-temperature-to-body-temperature range.
Over-engineering is never good. A proper quartz crystal designed for timekeeping purposes will be just fine for a network of electromagnetic slave clocks. It is already orders of magnitude better than the electric master clock that originally drove them.