The internet is full of scammers and scams, and so you have to approach any given opportunity with great care. The world of Au Pairs is no different, with some scammers creating a fake Au Pair or Host Family profiles in order to trick people out of money in any way that they can.
The main aim of the scammer is to extract money from you, and so anyone asking for money, especially sent via international transfer services such as Western Union or MoneyGram should arouse suspicion. However, they are also very clever, and try not to make it too obvious by asking for money straight away. They can be very convincing, building a rapport with you first, before asking for money with a perfectly valid sounding explanation, even going as far as providing legit looking paperwork.
If you are a host family, a fake Au Pair might ask for financial help for travel and relocation costs. As much as you want to help with this, it is vital not to send money abroad as this is a common scam, and so it is best to reimburse them once they are with you. Another thing you can watch out for to protect yourself from Au pair internet scams is remember it is usual that the Au Pair will pay for all their own paperwork, anything paid for by the host family should be written in the contract before signing, and not asked for afterward.
Other common internet scams for Au Pairs and Host Families include correspondence from fake travel agents, fake lawyers, fake Au Pair agents, those related to host family checks, and similar. Anything asking you to send money to a Western Union account or via a similar international transfer company is a sign of a scam, as such transactions can not be traced. Other common scam signs that occur is that a sudden tragic accident or illness happens and they really need help financially, they are stuck at an airport and need money, or perhaps there is someone claiming to be an official but with an obviously amateur email address or bad grammar. Keep an eye out for such behaviour.
As an Au Pair, you should check out the level of pocket money that is usual for the country and the area you are headed, and if you are promised a much higher amount, be very wary.
Basically, by going through a reputable Au Pair website or agency and only corresponding via this website, this is something you can do to help keep on track. You can always query or report any suspicious behaviour you experience with the potential Au Pair or the Host Family. Most importantly, do not send money unless it has all been arranged and contracted beforehand, and if you must, then send it through a trackable and legitimate means, NOT an international transfer service used by scammers.