traveled several times with my rackets.
low-cost within Europe.
"regular" airlines within Europe.
"regular" airlines transatlantic flights (Europe -> South America).
charter flights, part of holiday package from Europe to Africa / East.
Both types: checked luggage and cabin luggage.
I haven't experienced any issues when I had my rackets as cabin luggage. Also didn't experience issues when I took my umbrella in the cabin.
In the past I could as well easily place the rackets in the checked luggage, but several times I got my checked luggage with bumps, and one of them was significant. Luckily for my rackets, they were not there. So, since that experience, I don't place voluntarily my rackets in the checked luggage.
Additionally, I recall Monfils 1 or 2 years ago, on a short flight within Europe with a reputable carrier had all his frames destroyed in checked luggage.
Some other stories mention lost luggage, which is almost "as good" as opening your luggage to find the rackets destroyed.
So, long story made short, if there is a chance, I won't place in checked luggage important and valuable to me items, my tennis rackets being part of the valuable to me items.