My feeling is that young kids (say under 10 years of age), regardless of their not yet refined technique, are not strong enough to damage good cymbals. Sure, they may use a stiff grip and smack hard etc, but their tiny little arms don't weight much and they don't have the type of brute strength that can really harm a cymbal. I don't think any good cymbal is truly in danger here.
But, what is perhaps more of a concern, I feel it's very important for a serious, aspiring drum student to be using excellent gear. Some of the el-cheapo cymbals I've checked out in my day were truly garbage. You can't make music with that type of stuff. You can't refine technique etc when you're using equipment that will never sound good, regardless of how you hit it. Etc. A serious student should be using good gear... so they can learn how to make that gear "sing". Cheap, crappy gear will never "sing".
A few years back I bought a relatively inexpensive kit for my 3-year old.... and I made sure to tune it up well and added excellent cymbals. Overkill? Maybe. But at least she will grow up hearing and becoming accustomed to "good drum kit sound". In my opinion, she will learn how to "work" the kit way sooner this way and have a better understanding of good sound.
So, in sum, I'd say it should be fine, and is even recommended, to let young students use good cymbals.
If anything I'd be more concerned about having the youngsters knocking the cymbal stands over and having the cymbals crash to the floor. Hopefully you can trust your students to behave and be careful / respectful of the gear. And of course make sure to use good cymbal sleeves and felts etc and make sure they're always installed (because a student might choose to swap a cymbal and forget to re-install the sleeves / felts as I have seen happen).
That's my 2 cents anyway. Best of luck!