I disagree strongly with many of these responses. Your payment as a host is only protected if you keep all communication on the Airbnb Platforms. I never email, call or text outside the platforms.
As for many guests not being able to locate self check-in instructions. I use this work around.
My house rules state that I do not offer Airbnb Tech Support and guests having trouble with the platforms are to contact Airbnb.
Under "check-in Method" I select "OTHER" then I added. "Guests will be using the app integrated Self-Check-In Instructions. CONTACT AIRBNB SUPPORT IF YOU NEED HELP LOCATING THEM."
Even if you have a smart lock, lockbox, etc. if you put the code in "Check-in Method" guests skip over finding Self-Check-In Instructions.
As host we shouldn't have to communicate outside the app or give tech support. I do neither. I Stick to the app and direct guests to take grievances up with Airbnb. The more guests contact Airbnb saying they can't find Self-Check-In Instructions the faster Airbnb will correct the issue.
If you get a bad review on Check-in and the guests messaged in the App saying they couldn't find instructions and you advised them to contact Airbnb for Tech Support. That means it's a review without a fair/valid experience and can be removed. Guests inability to navigate the Airbnb Platform is not something they can take out on you.
Stick to directing everyone to the Self-Check-In Instructions and if they can't find them direct them to Airbnb.