Opponents giving your +15sec

Is there a way to unable your opponent to give you +15sec ?

Seriously, I hate this. They do it most of the time when you're losing on time but they do want to crush you til checkmate, but it pisses me off, just let me play with my left time.

I just played a game with some dumb guy who gave me +60sec.
I told him not to do that and only played when those 60sec had passed.

And this guy just kept on adding time, then complaining that I didn't want to play.

What do you think ?

I really don't mind this but I can see how this can annoy some people.

think for your allotted time and then resign :)

Just disable it from your preferences page

I don't think it's a good idea. Same thing has happened to me.

Solution: leave

Have it work against them and let your time run out.

Countless times already it was possible to win them using this additional time. It's even more fun than usual.
I won 3 times (3-0) yesterday in Anonymous antichess right after opponent added time in all 3 games in *almost* won positions.
At the end he lost 3rd time and even said "Well played".

So probably best strategy here: when you play such guy, try to make a lot of fast moves, get into troubles, and make hard thinking, like if your position was really bad. He'll bite on it before position is actually lost and will add time.

If position is already completely lost, then just add time in return. It negates effect almost completely. It's important though to add time faster than your opponent. Most fun thing is to win both in "add time battle" and onboard.

P.S. Oh and have strict rule to add time to opponent and say thing like good game only if you lost\losing. It's common behavior among strong players over 2000. It gets much much worse below.

Realizing a game cannot be finished on time and accepting bonus time, shows both humility and strength of character.
Simply say thank you and keep playing or if you don't want the bonus time then resign with finesse.

@thibault If the feature was to change, then I would prefer option number one:

1) Offer increment time, rather than the +15 seconds. Both players could benefit from the +3 seconds increment time.

2) Could the +15 seconds behave like a Draw offer. If a player continues to play after the offer was sent, then nothing changes and the extra time is not added on the game. If the player accepts then they get that extra 15 seconds.