Well, today I uh...

[Katharsis]

I've been playing two accounts on two computers for several months now. It's been very easy. Today, the shaman on my trial account reached lvl12 so I decided to set up my boxes for three accounts. I've got the main running all out at 1920x1200 on PC1. The two alts are running at 1600x1200 maximized on PC2. I use a toggle with Hotkeynet to bring a window forward on PC2.
<hotkey Ctrl Alt Shift W>
<Sendpc 192.168.1.4>
<Toggle WoW-One WoW-Two>

Using all new commands in Hotkeynet I quickly had my two alts following orders from the main. Yay! Then I decided to try out Freddie's new movement keys. I wrote the command below to send my two alts off to the side when my main took a step back.
<Hotkey DOWN>
<Sendpc 192.168.1.4>
<SendWinM WoW-One>
<KeyDown Q>
<SendwinM WoW-Two>
<KeyDown E>

<HotkeyUp DOWN>
<Sendpc 192.168.1.4>
<SendWinM WoW-One>
<KeyUp Q>
<SendwinM WoW-Two>
<KeyUp E>
I sent my trio to practice in South Durotar where they wouldn't get into any trouble while I experimented. Watching them move was like poetry in motion. Then something went wrong. The alt on WoW-Two went strafing north and repeatedly banged her head into a rock wall. While I spammed every key on the board to stop her WoW-One went for a swim in the opposite direction. I have no idea how I locked up the keys or what I eventually did to stop it but WoW-Two is now royally pissed at me and WoW-One ended up with a nasty sunburn on Echo Isles.

Later, things went much better in RFC but the beach incident was a hoot.

[Notes]

Can't help you with your problem but the story you added made me lol :D

[BobGnarly]

I've had a few similar situations that I couldn't explain either.

I use keyclone, and once in a while I will toggle off the DoNotPass feature, forget I did, then go on about my business, only to find my chars all running in different directions. Most of the time, I can just stop, turn DNP back on, hit my "follow" macro, and I"m set, but every once in a while, they won't stop for some reason. It's funny and frustrating at the same time. One time one of my toons was clear on the other side of the zone before I got it all back together again. :)

[Katharsis]

Yesterday I was all ready for some serious practice with three accounts. But then my Ergodex decided to quit working. Meanwhile the water heater decided to start leaking. I did a complete overhaul of my UI and am better off for it. This morning the plumber arrived on time, did a great job and didn't charge me an arm and leg for the quick service. I think my trial account is going to run out before Battle Chest arrives. Stoopid Amazon.com and Super Saver shipping. OMG, I might have to revert back to two-boxing.