Dear Humans and Dogs, Brothers and Sisters,
I am probably the first Dog hitchhiker on this Website ;) and I will try to provide as much practical information as I can about Dog Hitchhiking.
I have hitchhiked something like maybe 15000km between Spain - Poland - France. I have crossed many border even though I do not have papers, in your world it is so easy to become Clandestino... I have even illegally entered Sitzerland, successfully passing half an hour border control - probably my Swiss accent was convincing enough.
When I see a car stopping on the gas station I do not wait till humans finish their time consuming greeting process - I just jump into the most comfortable car I see.