Not sure if it's unprofessional, but I do find it needless and a but tacky. Why not use that signature space for something more useful?
Isn't that space reserved for however the owner wishes to use it? Who's to say that having the signature, "Sent from my iPad", isn't useful to the sender?
And while the iPad version isn't terrible, there are some truly awful carrier versions: " Sent on my Doohickey Formula 44 Smartphone, Powered by Verizon's Blazing 4G Network." Now THOSE look ridiculous and unprofessional?like giving someone one of those business cards that are "free" to you but have an advertisement for the printer on the back.
I hear you, but again, people are smart enough to assume that the sender is simply using the default signature that came with their device and unless it is something that's way out there, many readers will not give the signature a second look, in my opinion.
The worst, though, are the addresses themselves. Nothing says unprofessional like kittylovr3826@hotmail. Those boggle my mind.
Now here, I'm in full agreement and I'm my own worst enemy. My signature -Just Me, D- is known by everyone who knows me personally and if my recipients do not see that signature, they will doubt that the message is from me. Having said that, there have been occasions where I've sent business related emails to non-personal entities in which I had forgotten to delete my trademark signature for a more "appropriate" one and felt like an idiot afterwards. Hahaha. It doesn't happen that often, however.
Anyway, thank you for responding and have a pleasant day.