Surface finds on cultivated land are normally not considered to be of muchvalue since they are no longer in situ. Identify what you find and log it but, don't dig.

I did 4 hours of volunteering today at a local nature center and participated in an actual archaeological dig. The lead archaeologist did a corn chicha invocation thanking the people of the land and the participants before we began. The entire morning was spent setting up the 4 sites. Tomorrow the excavation begins. After there will be a native tree planted in each of the four holes.

Hi. I'm not familiar with the law over there, but getting permission from the owner of the land is certainly a good idea - especially in the US where some landowners may be a little overly trigger-happy.

Here in the UK "field walking" and looking for archaeological artifacts of the type you mention is considered perfectly OK by archaeologists - as you say, they've already been removed from their archaeological context by decades (or even centuries) of ploughing, and there are a number of important sites which were only discovered thanks to well-informed members of the public noticing an unusually high number of worked flints or potsherds in an area and notifying professional archaeologists that they may have stumbled across something worth investigating. What is frowned upon is digging - many sites have been badly damaged by treasure-hunters with metal detectors who don't record the exact position of any finds they make, thus rendering it without value from an archaeological viewpoint as @t1nick says.

With all due respect. Permission from whom? I sure you mean the land owner, but once removed the projectile point loses all its scientiuc informational value. This is just anither form of pot hunting. If you must remove artifacts, Im sure the state archaeologist has a cooy of the forms they use to record finds on legitimate expeditions. All finds should be properly documented to be of scientific value.

The government prohibits collecting, excavating, or otherwise disturbing historical and /or archaeological sites on state or federal lands. Cannor stop, except in certsin circumstsnces on private property. But its dtill unethical.