Here we see friends sharing a Costa Coffee scam via WhatsApp. WhatsApp promotional messages are a hotbed for scammers. Just because an 'offer' or competition is sent to you by a friend does not mean it is safe. 

I had a friend recently receive a WhatsApp promotion which was actually the Ryan Air free flights scam. Luckily they saw through it. 

Always be cautious to give always, surveys and competitions no matter how you are approached.