He tends to walk in front of her rather than with her. Common courtesy, is you wait for your spouse. She wears extremely high heels and perhaps it is difficult for her to keep the pace; perhaps Trump steps in line with others which leaves her trailing behind.
The current Trump criticism aside - this much is certainly true... I have been guilty of it myself, unawares.
Never in a dress and heels of course - I've had enough country etiquette thumped into me to treat a lady as a lady, and if she is decked to the 9's, I am almost instinctively, formally so.
It was my third real relationship - That was the particular girlfriend who informed me that it wasn't pleasant for her to be dragged along up a mountain... I thought it was helpful, and it still feels that way to this day... I am still prone to it... But her sitting me down and explaining it to me in simple factual terms, has enabled me to check myself at the first complaint. My stride is likely to be twice hers, and me stepping out for real is something most women will not be able to manage.
Your point toward common courtesy is not to be dismissed. True enough.