Airbnb guests not responding to Rental Agreement request

I would say that 7/8s of my guests who book through Airbnb don't respond to the triggered channel message with the Rental Agreement link sent immediately to them when they book. This requires me to manually send them an SMS with the link or to call them.

I'm having a hard time understanding why this is. I'm not sure that the majority of them are just ignoring my request, figuring they can get away without signing.

The requirement is clearly and prominently stated twice in my listing - once in the description and again in the house rules. Guests are also asked to tell me that they've read the rules and that they work for them. Yet even when they do that they still don't sign the agreement without my prompting them a second time via SMS.

I can't help but wonder then if they simply aren't getting notification from Airbnb that this message has come through, which should have while they're still in the Airbnb app or webpage.

Otherwise, if they're not purposely ignoring the SMS, what else explains them not responding to it?

Coz it's Airbnb. Their guests think that rules are optional for them. Nothing you can do but keep sending the request. I also sometimes send them link to this Air help article https://www.airbnb.com/help/article/465

Problem with that article is this sentence they stuck in, and which guests have come back at me with:

"You’re not obliged to sign anything."

Yes, actually they are obligated if they want to stay at my place. 

But, again, my question, I suppose is really for OR techs to learn from Airbnb, is - Are guests not getting alerts/notifications when this channel message is triggered and arrives in their Airbnb message box?

I'm sure they are getting the messages. You can log into your Airbnb account and see the copy of the channel message sent from OR there in the Air inbox. And yes, they are "not obligated" - if they do not want to stay in your property. 

 Edited top add: I also have SMS trigger, and a trigger to send it the next day IF they do not sign form the 1st communication. I also add that they will not get access to the property without it. Usually works.