No, the usual practice is that usually one would select an activity he/she created when checking in new versions.
The "setactivity
" doesn't list any restriction in term of Identity when selecting the activity to use.
An activity is here to group some tightly linked changes together, changes being new versions on files or directories for a given component on a given stream.
There is no real "standard guidelines" except to keep linked changes together.
You could prevent the creation of activity (except for a project manager) with a pre-op trigger though.
I suppose another trigger might be able to enforce the selection of an activity only by a specific resource, emulating that way the "assignment" process.
But I rarely seen that implemented (or only when use with a link with ClearQuest).