Especially those that give us fair warning that they're auto filled and that they don't play that role well, at the very least if you can not expect them to play that role at the level of a main of that elo. So if anything give them tips and encourage them instead because being negative is only going to make them play worse.
Also, most players should recognize the pool of champions that can be flexed (in solo queue, not talking about the LCS stage) from A role to B role.
Knowing that Lux/Vel'koz/Orianna (mid laners), Trundle/Camille (top laners), and Ivern (a jungler) can be flexed to support could be the difference between feeding your ass off when being autofilled support and being a positive aspect to the team when being autofilled support. The idea is "It takes a different build, but the champion's mechanics are one less thing you need to try to learn in the space of one game". Someone who plays Lux mid (even if they're not a Lux main but have a fair number of games on the champion) would have a far easier time playing Lux as a support than trying to play Rakan or Janna support.
