Gidday,
Singapore Airlines are now telling you to keep your shoes on for takeoff and landing in the revamped vidio, featuring the ex DFO Training as the lead.
You will need your best footwear to run away from a serious accident as said before, the debris from any hull damage can be life threatening, even IN the Aircrafy if it breaks up.
As for dress codes, even in Internation J class the yobbo element is there, hate sitting next to the hairy armpit brigade, unwashed and rude as well.
Have done 13 International sectors and 2 domestic this year and it is a reflection of the times I guess, some people need to be on a leash when out they really do.
C YA