I had the experience recently at our Cafe Aroma meetup of being surprised by the seating: at this venue, it is entirely bistro-style tables with a maximum capacity of 3.

Perhaps we don't need to sit completely together at every meetup. It is up to the event host to decide if the seating is right for the type of meetup they have in mind. But I think we should be aware that there now are more and more coffee-shop-type places where counter seating and bistro-style tables is all that is available. And/or some or all of the tables may be unmovable (bolted to the floor). So if you want to sit together and you're not sure the venue has appropriate seating, it's best to contact them first, especially if it's a coffee shop.

I was able to send an email from the website of the coffee shops where we have meetups pending (Local Coffee and Bagel Factory), so we'll have answers soon about them. You could use these same questions for a phone contact or email to a venue you are considering for a meetup:

"Is most of your seating at counters or at small bistro-style tables? Can the tables be moved together? What is the largest table you have? I am in a meetup group and we like to sit together. Thank you."