I will break my response into two separate sections.
Flags indicator visible to any < 10k users
This is a bad idea. But before you just take my word for it, we should actually examine what kind of behaviour it could cause, and what purpose it would have.
First off, there are three kinds of flags. Offensive, Spam, Flag for Moderator Attention.
If a question is offensive, you should flag it. This flag is fundamentally about whether or not this is offensive to you. It doesn't matter if other people have flagged it as offensive, because you are not making a judgement call about them, you are making a judgement about your own personal opinion.
If you notice that other people have flagged it (presumably as "offensive") does it make it more offensive to you?
Will you re-read the question and find out that it is in fact offensive?
If so, then the feature has already become negative, because it is causing people to modify their behaviour. When it comes to offensive we want users to be making their own judgements.
Spam is largely similar. The post is either spam in your opinion or not. The opinions of others don't really matter here.
Flag for moderator attention
This should not be included in the indicator, becasue they are fundamentally different. They aren't necessarily negative, they might just be an indication that a moderator's attention is required, and are not commentary on the post itself at all.
That means that if these flags DO appear they are actually misleading the users into believing that someone has flagged it in a negative sense. As I mentioned earlier, this is something we don't want to do even when it is accurate, so we certainly don't want to do it when it is wrong.
Having flags visible to all users is extraneous information that not only do they not need for anything, we actively do not want them to act on it. So why provide it to them?
Flags indicator visible to >= 10k users
This makes sense at least, because the 10k users already have a tool which enables them to view all flagged posts, and all the flags on them. However, this tool is to draw attention to the flagged posts. It is operating under the assumption that the flagged posts need more attention in order to (possibly) be closed down and that the mini-moderators (10ks) should be the ones who go and investigate.
Becasue the premise is that the user has not already seen and evaluated the post themselves, it is superfluous to add an additional marker on the page itself. Once the user has read the post, it is still up to them to personally decide whether or not it is offensive, and the flags of other users should have no bearing on them.
So even at this point, although it isn't information they shouldn't have, it is still information that they simply don't need.
There is no reason to implement this feature.