If you run around at max speedhack someone's bound to find that a bit odd.
In terms of being detected. All I see Arenanet talking about is Gold Sellers and people who hack official accounts such as brute forcing and the usual password steal ways to get into your account. So far they have never indicated that "hacks" are a problem.
Nor does the game have any methods to properly provide feedback about this issue. I have been doing this with M's hack for weeks now, and apparently, over 1600 people have been banned for Botting. Yet I am still here.
Speedhack on 6 or less and no one will notice. Teleport as well, With GW2's overflow system people are constantly appearing out of Overflow. So it's not so uncommon. People generally don't care all that much unless you actively abuse it to for example max speedhack away from a zerg. That might be suspicious.
1 = Normal
6 = Speed Boost Style (no one will notice the difference)
7+ = Super Obvious + Jump Skip Ahead
As a side note, I did hear about ArenaNet saying that they got data analysts involved to find a way to auto-detect botters etc. Of course we are not botters. But with data analyses they might still be able to detect things out of the ordinary.
So we'll see. In my opinion, the less people that know about this, the better. If you use it and you don't want to get banned, then keep your mouth shut about it. Definitively do not post in Official GW2 forums/chat/channels.
If you wanna talk about it like now, or w/e do it on forums like these.
As long as it's free, ArenaNet can just as easily download and investigate more easily to try and detect it, so there's always the risk. But right now, it seems they have other priorities.