Our policy meeting is upstairs, and the organiser says someone can help with the steps

The venue confirmation came with a photograph of a narrow staircase. I sent it to the organiser and asked about the lift. "There isn't one, but people are helpful," he replied.

We are planning an open discussion about the town's transport priorities. One of the invited residents has already said she cannot use that staircase. The organiser likes the room because it is free and near the bus stop. I understand the budget problem; I've also heard him say this meeting needs views from people who find travelling difficult.

He wants to keep the booking and offer a phone call afterwards. She hasn't agreed to that arrangement. I don't want to decide on her behalf that a call is enough, or assume that changing the room will be easy.

How do I raise this as a problem with the planned meeting, rather than leaving her to explain why unspecified help won't get her into the discussion?