At the Bournemouth convention we would spend most of the sessions in the car. This was because we had a son who was hypersensitive to noise, light and if uncomfortable would make a fuss. We had tried sitting in the stands but had one rude sister tell us if we couldn't get our son to sit still she would be forced to leave. I told her not to bother we would go and never sat in the stands again.
The car gave the children leg room, they could get up and go to the toilet without causing a disruption and if necessary we could find somewhere shady to sit. The programme was on the radio and we didn't have to deal with selfish people. When they then stopped having car parks and told us all that we had to come by coach we just refused to go.
I did seriously consider finding a nice park somewhere close enough to pick up the reception and park there without going to the convention centre.