Hey Peter,
I'm in agreement with your Ops and events teams that you should absolutely be scoring (RELEVANT) event engagement! The scoring values themselves I'd say would be for you to determine yourself based on the quality of your engagements at events and trade shows compared to the other activities you are currently scoring. Is visiting a booth at an event more or less valuable than a webinar? That's for you to either prove out with data, or to make an educated determination by understanding what activities typically lead to better sales outcomes.
My question is HOW the data is received back to you. If you're getting lists of people with various outcomes (attended the event, visited the booth, met with a rep) or something like that, you can upload or match those lists with your Marketo database, and score those engagements appropriately using a Smart Campaign. The way my team does it, is our events team creates an SFDC campaign for each event. We have a naming convention that utilizes a hashtag scheme to dictate the value of the interactions of the members of that SFDC campaign. For example, we might see a SFDC campaign added for YYYY-MM-ABC_Company_Event-#Score1
That "#score1" is what Marketo trigger campaigns are listening for. The trigger "Added to SFDC Campaign" and campaign name contains #Score1, we modify their activity score. You can name those hashtags whatever makes sense for your business, they could just be tiers like I showed here (Score1, Score2, Score3), or the actual outcomes you want to score (#Meetings, #BoothVisit, #BreakoutAttendee, etc.). Why I like this is, we're able to also write an interesting moment that feeds into Marketo Sales Insight with the name of the SFDC campaign. For our events team, this gets the activity scored, and the name of the event in front of the sales team simply by following the little naming schema we've setup for campaigns.
Another option is to use campaign status' in SFDC campaigns. Upload your list to an SFDC campaign with the member status that is based on the engagement at the event, you can then have Marketo listen for that as well. This requires some custom status' setup from your SFDC admins, but this is definitely a nice way to go. Then you'd have every single attendee to an event in a single SFDC campaign, and each member has their unique status for that event, and those status' can have different scores associated on the lead score.
Sorry for the long, rambling reply. Just some thoughts I had reading over your question!
TL;DR - You can upload lists and score them directly in Marketo for the easiest solution, or you can get integrated with your CRM's campaign features to dynamically score event engagements based on each person's level of interaction with your company at the event.
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