Well, in some cases, I actually would. Starmie (or anything in this case) is going to be hit by a x2 move, so I'll take the hit for good reason then know if I can do more damage or KO the Pokemon in return. As for Dragonite, I wouldn't leave it in against something I know that has a Ice-type attack, like Starmie, or Lapras (or Chansey, and so on). Raticate has one of the lowest Special's in all of RBY (it has a base 50 Special, tied with a few other Pokemon as well) and it 2HKO's Dragonite with a non-CH Blizzard.
Kangaskhan, who has the lowest Special (40 Base Special) in all of non-gimmicky competitive RBY Pokemon learns Blizzard too, but it's not recommended on it as it has better options to use against such threats, so that's why I mention Wigglytuff over the rest of the low base Special Pokemon, not to mention that Blizzard is one of the choice moves in it's RBY analysis. Kangaskhan scores a 3HKO on Dragonite with a non-CH Blizzard. But the point is, if Raticate scores a 2HKO with a non-CH Blizzard on Dragonite, then the superior Special threats in RBY (like Starmie) will most definitely OHKO it.
Clearly what I'm trying to say is that lots of things get 2HKO'd in RBY, but Dragonite seems to be one of those Pokemon that gets OHKO'd for sure by an Ice-type attack and risking the hit is not worth it (it's like not risking the hit against your Gyarados in DPPt if you predict the obvious Electric-type move coming at it). You know it wont live the blow and strike back like other Pokemon that stay in, take the hit, live it, then strike back and KO the Pokemon in return or greatly damage it, as planned.
~ Aether Nexus