Laces
The colour of these can be important. Many SM Skins wear WHITE laces which should not be mistaken for the signal of "Vanilla". Other common colours are RED for guys into Fisting, YELLOW for piss, BLUE for fucking and BLACK for non-disclosure.
However there may be many other interpretations due to local customs:

WHITE

Political: White Power Skinhead -

Sexual:   Skin into heavy SM  - not a fashion skinhead, hence the possible association with white power (like as Hard as them), it also was associated with skinheads that supported National Front in the UK.
Fashion: White goes really well with Black boots.  In the UK more likely that the guy is into SM and has indifference to politics.
In Northern Europe there is more sensitivity to the politics.  It is more likely that you are a real skin if you wear white laces due to the hyper reaction  - for a quiet life you would not wear them for fear of what people might think.
In Amsterdam there can be some over reaction from non-white people (cries of 'Black for ever' have been heard). A strong prejudice about your assumed politics is made.

Red

Political: Red Skin  - opposite spectrum to the white power, pro-communism, may encapsulate the 'SHARP' Skin politics "Anti-Nazi League" (consider two groups that hate each other - both as extreme as each other one wears white one wears red). However in the UK it also meant that you supported the British National Party (as the National Front were not extreme enough and these were the REAL Skinheads etc etc).
 

Sexual: Skinhead into Fisting

Fashion: In Northern Europe there is more sensitivity to the politics.  
In Amsterdam a lot of people are into Fisting so might wear red, not so in some parts of Germany where the politics still holds. It is still assumed that you have chosen a side so - for a quiet life you would not wear them for fear of what people might think.

Yellow

Political: None known
Sexual: Skinhead into Piss possible much more.
Wearing yellow and brown + rubber usually is a good indication that the guy is a dirty pig.
Fashion: Yellow goes really well with Ox-Blood boots.

 

Blue

Political: None known
Sexual: Skinhead into Fucking

Black

Political: None disclosed
Sexual: None disclosed
Since you made no effort to change the laces it implies that you are not making any statement.

Other

This tends to be limited to the stock available from the DM supplier, and red&white stripe laces would cast doubt on the guy anyway - bit like a carnival queen.  Would you really want to have sex with this type of guy?