I don't know. I do know that passer's by probably wouldn't think.......'that child looks dead to me'.
I'm pretty sure I've been in this position before, walking home at night on holiday, other holidaymakers walking in the opposite direction carrying a kid in exactly the manner described. I wouldn't assume 'dead child', but may wonder why he/she wasn't in a pram.
I don't know if you have walked on calçadas (Portuguese paving cobbles). They are used for being durable, not for being smooth. Pavements are normally 'rugged', so often people choose to walk on the tarmac of the street instead.
Best information suggests (I say no more than that) that Smithman headed down the Travessa das Escadinhas, the passageway of little steps. The title is misleading. The steps are very much on the large side.
All in all, that route is not buggy friendly.
It suggests (again I can say no more than that) that Smithman was travelling a short distance and knew the local terrain.