I have never encountered a SMD part that needed to be hand soldered.
Probably what someone ran into is a part that needed a special profile such that the board would have had to be run thru the oven twice. If this is due to a single part, it could well have been more cost effective to run the board thru the normal process and hand solder the special part afterwards. It's not that it couldn't be reflow soldered, but that for that process in that situation it wasn't economical. I have seen this case a few times.
Another case I've seen a few times is when there are only a small number of parts on the bottom of the board. Two-sided reflow takes some special handling, and for a very small number of parts it's more cost effective to run the normal process for the top side, then add on the small number of bottom parts by hand.
More stuff is hand soldered than you might imagine in places where the labor rate is low. A factory one of my customers used in China had a whole manual assembly line right next to the more automated pick and place and reflow line.
Again, it is highly unlikely what you heard is due to a part needing to be hand soldered due just to the part itself. A assembler may have said they "need" to hand solder a particular part, but that was due to their process and tradeoffs, not inherent to the part.
Best Answer
It 's possible by hand when you're very experienced with fine hand soldering, but for lesser souls it's also possible with solder paste and manual reflow with a hot air (rework) station.
With reflow, the part will align itself and solder will 'suck' towards the pins and pads.