but since it is informal and easier to get the information I'm agree with that as a showing agent.
But as a listing agent I rather to use showing assist or phone call and take notes. less work and notes all the way around.
if they do not reply back to you txt, it is a red flag to deal with this person.
I think the best and most proper way is via Show request so , this way you have a report to show to your sellers and all showing are recorded.
Texting is very common these days.. As for when I request an appointment I follow the instructions given on the listing. If is says call agent I call but, if the agent does not return my call I will text them..
But I definately prefer the first request through MLS.
I try to never go to a showing without a txt re-confirmation, too often people are late or just careless
and if you have to drive for 1/2h and a no-show happens, its frustrating for everybody... Answer YES
Our MLS has a great ShowingTime button that a Realtor can simply "Click" to arrange a showing and it can send a text to alert the owner occupant, too.