This is definitely an issue of what you feel comfortable to do, but I would encourage you to not worry about telling a group you are teaching and will give you a couple of examples of why not:
When I was in junior college I had a professor who was a type 1 for my psychology 100 class and I liked how he told the class.
It was in a big lecture hall and on the first day probably around half way going through the syllabus he said as he took a sip of something,"By the way I am a type 1 diabetic so may have to sip on something to keep my bloodsugar up. I am not a type 2. I don't want to hear any of your advice, etc....."
He went on a mini-lecture about it, saying he had to tell us in case he ever needed to stop lecturing to have some sugar- gave the class a mini-lesson on it and I remember him saying he didn't want anyone coming up to him after class asking him questions about it, giving advice, asking dumb questions about it or telling him horror stories about their relatives that had limbs amputated because of it- he was pretty blunt about it and funny too- since it was a psychology class he did talk about human behavior as it related to diabetes- but kept it to like maybe 5 to 10 minutes and then that was it.
Since he was the teacher, he had a forum to educate, lay out the ground rules about it and did it in a good way. I was glad he was able to educate the audience about it, but at the same time never made a big deal about it the rest of the semester. He maybe once or twice during the course of the semester, popped out a glucose tab or sipped some sugar drink and said, " excuse me just the diabetes thing , I don't want to pass out on you people" and then just kept lecturing.
The only bummer is that I really wanted to ask him questions about it after class since I had only had it for like a year and a half and really did not know any other T1's, but I had to respect his thing about not anyone asking him questions or approaching him after class about it so I never did.
Since you are the teacher, you really have the forum to be in control of the conversation and present it how you like and not deal with the condescension- or if you really don't want to and just pop a glucose tab or drink something sometimes while lecturing that is your choice too- but I am guessing that it would be hard to keep to yourself if you are lecturing alot.
Actually, I used to be a corporate trainer so was teaching all the time too. If I had a seminar where I was only going to teach the group once or twice, I didn't mention it. It just wasn't necessary. (I wear a medic-alert bracelet- always check my BS before a lecture- have sugar handy and had a co-worker who knew I was a T1 around)
But, sometimes I would be training a group of like 25 people everyday for 2 months- well, I would end up telling them because when you are talking all day in front of them, you get to know them and it is just a natural thing, plus sometimes I would have to take an unexpected break to test and I would just say, let's take a 10 minute break- they all liked that. I would then get some annoying questions after class, but since I was their supervisor in that situation, people were more hesitant to make inappropriate comments and careful with what they said since part of my job was reviewing their work.
Since you are their teacher and are in a position of teaching them, I am guessing you would get less people ,if not any, being condescending to you. I would be surprised to know people talking down to their professor! I never did. I didn't like all my professors, but still wouldn't talk to down to them!
So, in the end, you have to do what you feel comfortable to do and consider any safety issues- I have good hypogylcemic awareness and have never passed out in the 26 years I have had it and always have glucose on me- but when I was working, I did always let a co-worker know (eventually, after I proved myself to be a "normal" healthy person) so it also depends on your awareness and co-worker situation.
By the way, I have much better grammar, spelling too- I just never edit or proof or care about it when I email or text.