I started playing gst1 online for the wii since a few weeks.
A few times I thought my adversary was using cheats, because each time he served and I returned his serve whether it was in or out, he got the point immediately without having to play any further for the point.

Well last night it happened to me to! Everytime I served I got the point and the opponent couldn't do anything about it.
I am NOT using any cheats.

That's called the "serve-bug". Let me guess: you were playing against someone from Japan/Australia/Brazil or with a huge transferring before the game starts?

You cannot do anything about it(or serve slow, but that's not funny), only quitting against those countries or against huge transferrings.

Its happening to me more often now. today 3 times in my advantage..
Not on every serve tho. Played american, spanish, french and german ppl.
Its kinda anoying tho and rather unfair..

Another thing happened today in a match. No serve bug at that time.
At some point I was standing at the net wanting to lob my opponent.
All of a sudden I hit the lob extremely high. After a while the ball bounces back on my side of the court and i got the point.

Is it just me or do you guys do strange things as well ?