When a friend asks you to lie for them, they’re asking you to carry their weight with your name.

The request sounds like a favour and is actually a transfer. Whatever they did stays theirs, but the risk moves onto you: your credibility, your standing with whoever is being told, your problem when it comes apart. Friends who ask this often are not being cruel, they just have not done the arithmetic. Someone who has done it does not ask.

You can refuse the lie without refusing the friend. Telling them you will help with the actual problem but will not say that to anyone keeps both things intact. If they only wanted the cover and not the help, you have learned something useful cheaply.