While’s gmail’s filtering is obviously neither your responsibility nor under your control, you also can’t really fault people for using one of the most popular email services on the planet.
I would hope that your department follows up some other way (you surely have a phone number!). Searches are crazy time consuming and expensive, and grad student recruitment isn’t exactly free either.
Why not? Popularity does not imply quality. If it is a poor service, you can (and should) fault people for using it.
Agreed. There should be some give and take, some minor reputation at stake. It's healthy to have some people applying back-pressure against popularity. I like the idea that laypeople might hear whispers among their tech-savvy friends that it's not considered "cool" to have a gmail address. Much like having an aol.com email address was seen as uncool in years past. It's perfectly reasonable for some people to be working to give gmail.com a bit of that same reputation.
I haven't laughed this hard in a while. How'd that go with convincing people not to join walled gardens like Facebook and Insta?
And actually, more seriously, the reputation push-back on Facebook is finally reaching levels where laypeople are picking up on it. There's still a huge amount of ground to cover, but laypeople are now hearing the criticism of Facebook. You can see many switching from a state of ignorance to "I don't care; I have nothing to hide." Maybe in a few years we'll see more people saying "you know what, I do find these privacy losses bothersome." As with many reputation matters, it's a gradual process with give and take.
More broadly, grad school admissions--and, even moreso, faculty hiring--is already full of unwritten rules, backdoors, and tacit understands of "how things are done." It emphatically does not need more of those, especially petty ones related to email.
People's choice of poor quality service provider X impacts their ability to do their tasks when the service is poor. X can be email, insurance, banking, anything you externalize in your life.
The fact that a service is popular is a poor indication of service quality, if there is a correlation at all. Examples abound for popular services and products that are poor quality. Usually, the best services are a bit up, from the popular choice point, in the price/quality ratio. More so if there are free (as in beer) offerings in the market.
What's the alternative? Making sure that the recipient gets the message by sending a courier to his home address?
I remember when a buddy of mine, back in the pre-email days, applied for a job at a company. About a week later, he received a letter, asking him to call them. Turns out, he forgot to put his contact info into the application, but they were interested enough to look up his name in the phone book (they also have/had street addresses were I live) and write him a letter, hoping it would reach the right person. "Always put your contact into into an application" isn't a petty rule, and neither is "use an email-provider that doesn't randomly reject messages" in my book.
I would expect both sides to make a bit of effort. Applicants should check their spam folders and follow up, especially if there's a known timeline (American grad school offers need to be extended and accepted by the 15th of April, for example).
Institutions should maybe not rely on only an unreliable, unacknowledged form of communication. Since the applications usually collect phone numbers and addresses, a phone call or letter would be a very reasonable follow up; neither costs more than 50¢ to use. I think all of the PhD programs that accepted me did call and it seems like a good way not only to notify, but to actively recruit.