Yes, just tried it. May not sound as if I have a life, maybe not but I do actually have a 28" suitcase and a pair fenders some feet from my PC. A 26" held them but I wouldn't advise it. I'd use it myself but...... I do stuff like that, stuuff the operating word. Your man's from overseas so....
You know the suitacases in vogue now, the ones that are soft shelled and higher than wide with the slideup handles that roll ? A very standard size is 26", 28 too. 30" for a super safe fit. 36" rolling duffels are not uncommon. 29s also are a very popular size in modern luggage. I'm being S. Safe here.
These are very old Raleigh 27" wheel fenders, no flexibility taken into account.
Just re-read 26", have them too. Just think about it if you're skeptical; 26" wheels are just that, about 26 overall w/tire, NOT the diam. of the hoop which pretty much equals the fender. My 26" new ones here measure 25" with a 9" deep arc. if yours are full radius my afformentioned is WAY safe