On the one hand, I can see this. On the other hand, perhaps the argument
can be made that the company has more of other kinds of costs in hiring
both sides of a couple (e.g. both sides of parental/family leave; likely
overlapping/simultaneous vacations; etc.) that might mitigate the savings.
On the third hand, the company might save on health insurance, too.
On the fourth hand it could be argued that while a company must not expect
you to have new/unrelated roommates, that to equal your home conditions is
a reasonable level of accommodation. I guess that could be problematic, though,
if you and your spouse have separate bedrooms at home and that is really nobody's
business. But suffice it to say, for a married couple travelling, I do think maybe
there is wiggle room in how many rooms a company should pay for. Or at least,
it is *much* less clear than for an individual travelling with a co-worker.

When I worked in software, the company actively discouraged (i.e. no
referral bonuses, unlike for friends) relatives/spouses being hired. But my
sister/BIL do work for the same company, and were able to negotiate that
they got a discounted family plan insurance instead of two individuals,
i.e. the same company $$ but less that sister/BIL had to spend.

--LG