I can't answer your last question, but I'd say the chance you got two bad sticks isn't very high. For the first one, what do you mean by "locked up"? No response to the remote or no picture on your screen? If it's the latter, there's a "power saving" option under Settings->System->Power that if enabled will put the stick into a low power mode. Pressing Home on your remote a few times should wake it.
For either stick, it could be something interfering with the remote. The TV itself is often the culprit, but since it's happening on two different TVs that doesn't seem as likely a possibility. When you press a button on the remote the light on the stick should flash. It may be hard to see depending on how the stick is oriented. I would say to try the Roku app on your phone and use it as a remote to see if the stick is still connected to your network, but you can't use it on the second stick until it's connected to your network in the first place.
One last thing - more than one person has reported that the batteries that came with the remote were no good. Don't rule out dead batteries.
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