Post here all non technical related topics about Formula One. This includes race results, discussions, testing analysis etc. TV coverage and other personal questions should be in Off topic chat.
I'm pretty sure they have the blood group on the race suit somewhere too.....
Maybe bloodgroup stickers are less important in F1. It's a closed circuit, it wouldn't be too hard to get all that info on every driver to the medical centre/medical car before the races are run.
In each country, the National Sporting Authority, in accordance with local legislation or customs, must draw up and print a medical form for distribution to all applicants for a licence. This medical form must stipulate all the tests to which the drivers will be subjected, as indicated hereafter. It will be signed by both the examining doctor and the driver concerned, above the stamp of the ASN.
The prescribed tests are as follows:
a) determination of blood group and RH factor compulsory only in those countries where required by law..." (italics are mine).
Besides, the clothing regulations do not mention blood group stickers.
In rallying there are no T cars. If T car is for one driver only than it could have blood group sticker on chassis but if it is open for both drivers than such mark could only be located on seat, HANS, overall or helmet because they are unique for each driver.