We do use baskets and have since our renovation in 2006. When we re-did our course I wanted something unique for our flag poles. I considered poles only, no flagsticks at all (I still believe no flagsticks in a green would make little difference to the score for 95% of golfers), balls, and spheres of all shapes.
I really did not want to "copy" Merion and then I came upon an old turf magazine from the 1920's I think--Stumpf's was its name.
There was an advertisement in the magazine for "Wicker Balloon Baskets". These were mass produced baskets ($7.50) and the advertisement touted their advantage over flags for inland courses where wind was often insufficient to blow the flags enough to be visible. The notion was that the balloon baskets were more visible than a limp flag.
Anyway, I discovered many courses and not just Merion used baskets. I think Stoke Poges and I am certain San Francisco Golf Club use baskets. Anyway, since I no longer felt guilty about "stealing" the ice from Merion I decided to use them at Rivermont.
We make our own baskets. We purchase and soak the wicker, weave the baskets and paint them ourselves. Our baskets are yellow and slightly larger than those at Merion (theirs are red and orange--I forget which color is used on each nine). Anyway, we have experimented for years and have developed a very sturdy and handsome looking basket. In fact, our basket maker makes baskets for Sea Island now and we sent one of our baskets (painted navy) to SFGC for an anniversary of theirs several years ago.
Anyway, I like the look and do think for a parkland course with relatively little wind, the baskets are more visible than a flag draped against a flagstick. I will say that I think the notion that the basket was meant to disguise wind is a bit of a myth. As mentioned earlier, I think the purpose was to assist golfers in seeing the flagstick, not any attempt to deceive them. And really, it's. not as if there is no other way to visibly see the effects of wind around a green.
Hope this provides a little info for some.
Happy Thanksgiving.