I have done that on budget airline. I think I flew Jetstar to Hanoi and carried racquets onboard before. But I use cloth bag and hence it is small. If you use huge racquet bag, I think you may have to pay for it.
From my experience in europe-travelling: I once bought rackets and a bag (medium sized li ning bag with shoes in the shoe compartement and some clothes). i was allowed to carry my bag in the luggage. i flew with qatar and then (from barcelona) vueling. The people in the eu didn't even look at my bag, and the qatar check in staff only care about the weight, which after i say it contains fragile sport equipment, they don't even weighted it and gave me a fragile sticker to go along.
Sometimes airlines are more lenient when the flights are not full. I travel quite often between London and Hong Kong, when it is high season like X'mas, they weight everything, they stop people from bring more than one hand luggage. But if you fly during the low season where the planes are only half full, I have seen people 5kg overweight without being charged, three hand baggages without being told off. As for security, I think even the UK airports are somewhat more relaxed now, except for liquids and some odd items.
I didn't have problem for that to carry my racket bat. I always keep it onto my side bag. So no problem there at all.
Flew on Cathay to Malaysia. Four racquets in a cloth bag taken on as hand luggage. Absolutely no problems.
Last October i experienced new ruling from Soekarno Hatta international airport; that the rackets cannot be brought through hand luggage. It is not the ruling of the airlines; lucky for me, the guy in check in counter was kind and separated my rackets in a special checked in baggage. Funny thing....
