Highly enterprising of the vagrant!!! ( esp with all this rain!)
Yes- tis a problem if they are drunk...have you gone down and met them with someone else in tow??
They may actually be pretty harmless- esp if they're not nicking the strawberries and other veg.
I think we always presume the homeless are trouble makers- but you may be wrong in this case?? ( probably not...but you need to check first surely??)
(Perhaps they'll do a bit of weeding for you in exchange for some veg??

)