Ok this is what happened since my last post. I actually called one other Apple service centres to "innocently" ask if exchanging my Ipad for a new one would actually resolve the "cellular" issue; this third customer service person gave the same advice as the first Apple customer service person I spoke with, i.e. she proposed that I perform a restoration of my Ipad through ITUNES. If this still does not resolve the issue, I could then consider bringing my Ipad down for a fix or an exchange.
Therefore, I decided to just bravely go ahead to do the restoration through Itunes (of course this meant clearing all the content from my Ipad, but fortunately, I just bought it so there wasn't much of that in the first place). To my surprise, there were actually some Ipad bug fixes that came with the restoration process! Wouldn't this mean that for those of you who bought your Ipad a while ago and have not done any restoration, then your Ipad could not have possibly received these bug fixes??
Anyway, Itunes listed this list of bugs that would be fixed with the restoration process (too bad I did not copy the list or I would have reproduced it here). In the list, there appeared to be no mention of any bugs involving this "could not activate cellular network" issue. Nevertheless, I forged ahead and went through the restoration process. After the restoration was completed and I placed the SIM card back into my newly restored Ipad, VIOLA - the problem appears to have been resolved!! I then went to different parts of my area to "deliberately" lose the wifi connection to see whether the "cellular network" problem still exists, and to my great relief, the cellular network took over just fine, with no "could not activate cellular network" message appearing. I would still continue to monitor and report back on whether this "miracle" fix happens to be just temporary, or whether the restoration process has really succeeded in resolving this cellular network bugging issue. If it turns out to be the latter, could it be that the fix for this "cellular network" bug has been "quietly" slipped in as part of the restoration process??
For the moment, I'm just glad that the restoration appears to have resolved the issue, as I certainly dread the thought of having to make a wasted trip downtown to replace my Ipad, only to find the issue still surfacing later (as confirmed by FazerWiz). 🙂