Some quick math from data on @BCFerries Twitter account: At least the equivalent of 2,939 cars were transported between the mainland and Vancouver Island on Friday. The equivalent of 204 more cars came onto the Island than left it. Here's one example of how full the ferries were.

I say "equivalent" as there's no way to know with the data I have the size or type of vehicles and how many were actually carried. This also doesn't account for the number of people in each vehicle or any foot passengers.

On the Vancouver to Sunshine Coast route, two @BCFerries sailings for Friday are already booked solid.

On Monday, there is already one sailing back to Vancouver from the Sunshine Coast that's fully booked, but no full bookings for Sunday. This suggests that people are going there for the long weekend.

Update: There's already four full @bcferries sailings to the Sunshine Coast today from North Vancouver.

Three out of four @bcferries sailings from Tsawwassen to Swartz Bay today are already full.

All @bcferries sailings today, except for one, are already fully booked from Vancouver to Nanaimo.

Okay, more context, "fully booked, standby only" means that 40-70% of the deck space is reserved. Here's what the 9:45 sailing to the Sunshine Coast looks like right now.

Here is the line of vehicles going to Victoria from Vancouver on @BCFerries 11a.m. sailing. Ship is 80% full.

Next ferry to Nanaimo from Vancouver is 100% full. https://twitter.com/BCFerries/status/1248687299820433412?s=19

MP for Nanaimo-Ladysmith @paulmanly is calling on the Prime Minister of Canada @JustinTrudeau and BC Premier @jjhorgan to immediately restrict all non-essential travel on @BCFerries. https://twitter.com/paulmanly/status/1248762644309225478

For anyone following this, Provincial Health Officer Bonnie Henry's response to the question about the ferry traffic to Vancouver Island and the Sunshine Coast this weekend was that @BCFerries said traffic was down compared to previous years—when there was no pandemic.

I heard back from the @BCFerries media contact. They asked me to check back with them on Tuesday about the number of passengers the ferries carried this weekend compared to last week's numbers. They also said the traffic numbers for March 2020 are not yet available.

Just to tie up this thread, I did hear back from @BCFerries about my request for last weekend's numbers. They told me "on a system level, passenger traffic was 14% lower this weekend (9-12 Apr), than the previous weekend (3-5th Apr) & Vehicle traffic was 18% lower."