To answer the question is it a common solution, I have no doubt many sites and services do do this. Indeed their are a raft of companies that actually offer setting up fake or puppet accounts on your behalf.
Should you do this, that's a different question you have 3 distrinct areas to think about; Legal, moral, return
- Legal: Is it actually legal in your country/server country/target country to create fake personas for example here in the UK the creation of fake personas is consider a form of fraudulent advertising and could see you being investigated by the Advertising Standards Authority. Other countries have similar rules.
- Moral: Would you do business with a company that tricks it's customers? Is it right to lie to your customers and what would be the consequences if you were found out for your reputation?
- Return: Does it make financial sense to do this? Would a better return be to develop actual customers and build up your brand. What would be the effect on the return if caught?
Put another way fake profiles are a cheap trick that won't help build a community, their use would be strictly limited and to do them in such a way as to not be obviously fake requires significant investment in time that could be spent actually building a community with real people.