Re: About linked data integrity issues: protecting from updates

if you want to refer to information that you don't want to change, then you
should include that information as it was presented at the time.

for example, instead of doing this:

```yaml
id: #activity
type: Like
object:
  id: #object
```

do this instead:

```yaml
id: #activity
type: Like
object:
  id: #object
  content: "I hate Hitler"
```

even if someone fetches #object and sees that the content is different ("I
love Hitler"), at least your copy of it doesn't make a claim you didn't
intend.

more generally when you cite or refer to something, you typically include
the relevant cited or referenced material. if the source material changes
after that point, it's no longer your concern because you should refer to
the material as it was accessed, not as it may be updated in the future.
for example, many citations or references of web resources usually include
a "date accessed" at minimum, and possibly an archived or cached copy.