good idea! or, just say you saw it and were wondering what they've got in it, cause you're a herp lover too.common ground always makes things a little easier! if you go about it like you're interested in a positive way instead of a negative, they probably won't be so put-off by you asking. just be like, "hey i've got a few reptiles myself and i was wondering what you've got"
if they say its something that needs to be inside, just politely say somethin like, "oh man its getting a little hot here for him isnt it??", or "yeah it's about that time of year so i just moved all of mine inside cause its too hot now" (even though they weren't outside, but it would keep them from thinking you're telling them they're doing something wrong). I work in a pet store and i'm always having to tell people what they're doing wrong, so i've kinda got some practice at it lol. hope this helps!