How to spot a genuine accidental text?
Tricky, but ask why do you need to. If you don't know the sender and it's clearly not for you then just ignore.
In this case:
It was WhatsApp - they'd need to add as a contact, a quick look at your picture would be enough to tell them it's not Liam if they were a genuine friend of his.
The number is from another country. Often the Philippines, China, Nigeria, Brazil, India, Turkey. Massive red flag 🚩
The photo is of some hot young woman - additional potential to harvest data or extort money.
The message is clearly not for the recipient (not called Liam) and it contains a call to action with some urgency (missed lunch) which may compel you to reply.
They add emotional, authority or time urgent content which all could trick you into giving up info.
You may reply because you think it's a genuine wrong number. Or because you think it's funny - you've given them what they wanted. Simply don't reply. If it's a genuine error then the sender will realise eventually on their own.
You may reply because you feel you're expecting the text. Is it the Inland Revenue asking you to click the link and fill out info relating to that tax return that's due next week?
Is it the government threatening you with a fine because you've missed jury service?
Have you won something? You entered a Facebook competition just earlier today on the Plough Hotel York page. You've won a meal for 4! Wow, all you need to do is complete the form and they'll send the voucher. But look 👀 their profile pic is the same one, but it's from Plough.Hotel.York
(Another example of spoofing)
Is it your Grandaughter? Hi Gran, Please don't tell mum but i'm in some trouble. Im on a friends phone because mine was stolen and they've taken my laptop too. Please send me £600 and I promise I'll explain and pay you back when I can access my online banking. It's urgent, I need it by lunchtime or I'm going to lose my job. Etc etc.
This is just very basic. There are so many extremely sophisticated scams out there. The basic text from the Philippines is checking if your number is live whilst hoping you are a horny, lonely, extremely gullible male who will think a hot young girl would randomly and accidentally land in his WhatsApp. If that's the case then they might be able to extort some money from you or other valuable data.