I was in the store today talking to the Sprint rep and he told me that rooted phones are being searched out and accounts closed in breech of contract (fees, charges, etc). After some techie talk about other computer stuff, he finally broke down and explained that it was something with port use from other devices since almost all phone based apps use the same port/protocol.
Any truth to what this guy was telling me? Anyone here using other rooted devices and finding issues using other devices connected to the hotspot? I've used my laptop tethered using PDANet and it has worked for a long time but the IPad wants a wifi connection for certain things (facetime,etc). Any other "rooting" benefits besides removing bloat and stuff like turning on the wifi that are worth knowing in the decision to do it once its available for the 3D?
Thanks in advance
Late to the party here, and not sure if OP is still following the thread, but I think the OP misunderstood the Sprint rep a little bit.
He's not saying that they have some way to block uncommon port usage (although they definitely have that power). What he's saying is that they look for uncommon port usage as circumstantial evidence of unauthorized wifi tether. While they can certainly check for that (along with a bunch of other stuff), whether they actually do on a systematic basis is unlikely.
I would think that to become a target of an investigation, you have to really stand out in your data usage. Something needs to first set off a flag.
But before Sprint does anything punitive, everything that's tethered to your phone should work just fine.
If Sprint ever decides to collect evidence against you for tethering, all of the evidence will be circumstantial. What does that mean exactly? It means no given piece of evidence will be 100% conclusive, but it provides a strong implication that tethering is happening. Here's an example:
Let's say you've tethered your phone to 3 computers in your home, and someone on each computer is surfing the web on three different browsers. Each browser request contains a user-agent that gives away what browser and version you're actually using. My current user-agent is:
Mozilla/5.0 (Windows NT 6.1; WOW64; rv:5.0) Gecko/20100101 Firefox/5.0
Someone using IE, Chrome, Safari, Android, iOS, etc will have a different user agent. If Sprint looks at your data footprint and sees three unique simultaneous user agents being reported, that would look like tethering is going on. But it's circumstantial because it's POSSIBLE that such a circumstance can occur from just using the phone. You'd have to be spoofing user agents and/or using multiple browsers on the phone at roughly the same time and/or running some sort of load test or denial of service app. Very unlikely but still possible.
Add in what each PC is actually doing: one is reading CNN, one is doing a bittorrent transfer; the final one is playing an MMORPG, and this pattern can be established for multiple days... the picture becomes clearer. Still circumstantial, but it's more damning. Throw in what the OP said about uncommonly used ports, and that's even more circumstantial evidence leading toward tethering.
So it all depends on what you do while tethering that decides whether Sprint can collect convincing circumstantial evidence against you. If the only thing you do is surf while tethering (on one computer), your data footprint is going to look a LOT like using your phone barring the difference in user agent. But it is trivial to spoof your phone browser's user agent, so the circumstantial evidence Sprint could collect would be weak.
Given how many customers Sprint has, the percentage of users who are actually rooted, and the percentage of rooted users who actually tether, it's a really small number of people. And of those people, some percentage won't tether enough such that their data usage for the month exceeds that of the average user. I'm unconvinced that for now, unauthorized tethering is a threat to the infrastructure. Therefore, I don't think Sprint would go through the trouble to do a systematic deep forensic sweep looking for signs of tethering. Like I said before, they'll need a red flag first to narrow down the list, like someone using a disproportionately high amount of data.
But these are my assumptions based on my understanding of what I've described above, along with the fact that I've yet to hear anyone actually get shut down for tethering on Sprint. And if someone posts after this stating they were shut down, I'd be willing to bet that person used a ton of data doing so.
but being able to use the wifi hotspot with my ipad (without the monthly raping of $30 
) was certainly on the top of my list. 
