verklemming

19:00 Jun 10, 2013 

I see what you mean.

Your second interpretation is the correct one.

As far as your first interpretation is concerned, this should have required a slightly different phrasing, for example:

Spiegels, verlichtingsappendages e.d. mogen niet anders op de veiligheidsbeugel aangebracht worden dan door verklemming.
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Spiegels, verlichtingsappendages e.d. mogen niet op de veiligheidsbeugel aangebracht worden anders dan (gevaar voor) verklemming.

You are thinking these 'protusions' (Spiegels, verlichtingsappendages) may cause jamming ('verklemming') in narrow passages for example.

As to the reason why they should only be attached by means of clamping, I don't know, but it could be that other attachment methods are too rigid in case of 'verklemming' :-)

11:56 Jun 10, 2013 

the sentence is perfectly clear

11:02 Jun 10, 2013 

Agree entirely with Johan. IMHO, the Dutch sentence is absolutely clear.

10:54 Jun 10, 2013 

It seems to me that verklemming should actually be klemmen, i.e. only clamps must be used to attach these items.