Am I in danger if someone inflated my tire to 50psi if it only takes 30?
Only danger is leaving it over inflated . Put all the tires at what your door plaque has listed . And ask who ever did that why they did it .
Over-inflation is not good, as it compromises road holding and alters the car’s handling characteristics. The only thing worse than finding that one’s tires are over-inflated would be to not reduce the psi to the inflation pressure listed on the label that is affixed to the door jamb.
The recomended inflation pressure designated by the vehicle manufacturer takes into account the vehicles maximum weight capacity with people and stuff in it as well as desired suspension characteristics and the recomended tires maximum inflation pressure. As you add weight it compresses the tires more thus increasing your tire pressure. That’s why they tell to fill it to XXpsi unloaded. If it was at 50psi for a short while and they didnt fill it with 2000lb of people and stuff then you should be fine so long as you return it to the recomended pressure listed on your door. If your really unsure then have someone who knows a thing or two inspect the tires for signs of damage caused by over inflation.