[url=http://digitalcommons.wpi.edu/cgi/viewcontent.cgi?article=1053&context=computerscience-pubs]First person shooters are very susceptible to fluctuations in latency[/url] so it's entirely reasonable why you'd make the connection that you have. Regardless, there are a couple of fundamental concepts to understand here: 1) "Lag" is a subjective interpretation of an experience caused by latency or packet loss. Where a connection is [i]latent[/i] (slow to transmit/receive messages), the experience of "lag" increases. The important distinction between the two is that latency, in most cases, is what causes lag, but latency is an inherent phenomena in a network; all connections incur latency to some degree. Packet loss, where packets are dropped or corrupt, is an event where a packet doesn't arrive at its destination. 2) Latency can be exacerbated and packet loss increased by a [b]huge[/b] number of reasons, but very few of them are both deliberate [i]and[/i] nefarious. For example, if you were playing a game and someone in your house booted up a file sharing program which seeded large files (such as movies, operating systems, etc...) your upstreaming bandwidth - the pipe which transmits messages from your network to a WAN - becomes more constricted. The effect that has on you playing Destiny is that your router may: a) prioritise P2P packets over those from your game console (and especially so if it is configured to prioritise particular applications according to port numbers, physical devices according to physical address (ie. MAC), or network messages according to network addresses (ie. IP)), which means [url=http://www.cisco.com/c/dam/en/us/support/docs/voice/voice-quality/7111-pq-wfq.gif]the transmission buffer fills up with updates from your console stuck at the back of the queue[/url], and those messages subsequently incurring a increased queuing delay and consequently an increase in overall latency; or b) drop packets, resulting in packet loss, because the buffer is full. These events will result in the lag [i]other[/i] players see on [some of] their screens, as they haven't received the updates either at all or not fast enough, probably by exceeding an inbuilt threshold. However, what you should take away from this isn't that every single time you experience lag it's caused by someone's brother using BitTorrent, it's that computer networks are extremely finicky, sensitive things (just look at how and why poison reverse and holdown timers exist if you want to know more) and the slightest little thing can throw a spanner in the works, even though nothing evil was occurring. 3) Nevertheless, the video you've posted is actual evidence of cheating! Or is it? Take a look at the second clip - the enemy player was already moving around very irregularly [i]and[/i] continued to do so even after they killed the player. To me, this suggests they already had a poor connection and, just how I explained above, couldn't send messages to the other players fast enough, which resulted in the lag you see. It's no surprise then to see the enemy player had a red bar on the scoreboard. In my, unvalidated, opinion, if someone is cheating using the method that's at issue here, what you - and others - should see is a [i]very[/i] abrupt change in the game which then returns to normal after a [i]very[/i] short period of inconsistency, and which likely repeats at various intervals (likely not time-based) throughout a given encounter/activity. However, by no means am I claiming this is a foolproof method, as it still leaves a number of questions unanswered. 4) Although you probably don't want to hear it, it is very much possible, and especially so if you're encountering it every time you play, that the problem is your own connection. What I would suggest to anyone seriously thinking they are being cheated is to at the very least rule that possibility out. That means: a) checking the configuration of your router to make sure it's prioritising traffic from your game console and not your brother using BitTorrent. Try exploring your settings and looking for a section entitled "QoS", then create a rule for your Playstation or Xbox's address; b) understanding that the results given to you by connecting to a web server which hosts speedtest.net isn't going to be representative of how your connection performs when you're connected to other players with lesser quality infrastructure. Try a tool like [url=http://myspeed.visualware.com/index.php]Visualware[/url] and test for VOIP quality to different places, or simply pinging variously geographically placed devices during different times of the day.