I used to jobshare. Occasionally my jobsharer and I were both asked to be at work on the same day (training, big meeting etc) if we could arrange childcare, and our boss would pay our extra day's childcare.
I think the taxi home is also a 'perk' - i.e. something a good employer might do, but discretionary. And I reckon it would also be a taxable benefit (but Melissa/someone else better informed than me will confirm/refute).