I think you would upload it and send electronically. Memory sticks are best avoided unless you are 100% sure you know where they have been and use a very strong virus scan on it before you open it.
I have two dashcams - front and rear. At full resolution one of them takes 2/3 GB for a 5 minute clip, the other around 1GB. These would be quite large files to email.
Dashcams can be set to record shorter clips at lower resolution; they can also be edited (if you know how and have the software).