Tavares is a good example seeing as though there have been several threads started by people here who think you can just ignore contract conditions because you want to get rid of a player who isn't playing as well as you'd like. Sergei Bobrovsky is another good example, seeing as though it's another goaltender who got a big contract, underperformed it to the point that a highly touted first round pick was in line to replace him, and yet they couldn't unload the contract if they wanted to because, you'll never believe it, but he also had a full NMC.
You implied that it would be easy to trade Saros if Askarov outplayed him, just as Bishop was traded (a key difference: Bishop had only 8 teams on an NTC), so it's not exactly clear that you even knew Saros had a full NMC. I don't think it's definitive but history tells us that it's far more likely that NMCs won't be waived and contracts will be honored as intended upon signing so we should act like those odds matter.