The issue isn't buying over the limit.
The issue is making it seem like your account is hijacked, or part of a bot-net, or committing payment fraud (e.g. stolen credit cards).
Say you create 100 email accounts - john001@gmail.com, john002@gmail.com, john003@gmail.com etc. - and have them each buy a phone, and ship them to a single physical address. Most people would see that as a major red flag for something fishing going on.
Or say suddenly all of these otherwise unrelated accounts suddenly started ordering goods online, and shipping to a PO Box in the Ukraine.
As a consumer, I most definitely want all of this stopped.
In fact, my bank will regularly call me up and ask me to confirm transactions that seem suspicious (or send me an SMS) - if I don't respond in time (e.g. I'm travelling), they will lock out my credit card.
That is exactly what you want as a customer.
So in this case - it seems these people knew they were engaging in something shady - but perhaps they didn't put two and two together and think, gee, if I let somebody order something on my credit card, yet addressed to him, I wonder if it will look like my account was hijacked?