No, I don't think those should be of concern, Heinz.
If the primary users need a channel they will let us know.
The recommendation by the ITU ignores the lack of co-ordination between domestic allocations and surely only applies to inter-domestic activities since it would stultify use of 5 megs for longer range activities.
It is uncommon for an activation on 5 megs to last as much as half an hour, activators tend to run out of callers fairly quickly due to limited daytime range and limited numbers of chasers, and in any case will be wanting to use other bands, too.
In my book an activation is neither a local net or a long rag chew but is a short low power low impact event characterised by brief contacts which may or may not be with higher powered stations. In fact, nearly all of the 279 chases that I have made successfully on 5 megs so far this year were made with 5 watts to a sub-optimum antenna, and the great majority of the activators that I contacted were using 5 or 2.5 watts to an FT817. Activations tend to be short bursts of activity on an often somewhat somnulant band, not much given to net activity since the experimental phase came to an end with the end of the discrete channels.