I hear you! I can pretty much guarantee that most of my hotel outcalls will text me when they arrive, to tell me I can go there "now" if I like? As if I am sat around all day, waiting for their arrival!
Same when someone calls after months ( or even years) and assumes I have been sat there with suzzies on and car keys in hand - just waiting for them to say the word! 
I get this so much too & it's baffling. They'll confirm for a 1 pm appt, then text at noon & say they'll be here @ 12:15.
Takes willpower not to say, "So?"😆
If I'm ready, fine, come on up, let's get you in, get on with it, get it over with, get you out. Sometimes I feel mulish & say "We agreed on 1 pm. I'm not even at the hotel (feet up, watching Friends), I'll call you when I'm ready, which won't be until right around 1 o'clock.
They're always just shocked & they say, but I'm here now! I very politely (with the Hurricane Celeste edge to my voice) say, I am SO sorry! Did I miss a text where you changed the time? Did you want 12:15 & not 1? If so, why is the appt .... for...1 o'clock...? *my voice trails off uncertainly*
Yeah buddy. I'm making a point here & you damn well know it. I've never had anyone leave when they've arrived early to their session.