The paper focuses on questions such as: How much urban planners and designers really think about potential future users of places, whether considering strategic decisions about spatial changes or being concerned about their implementations? Where in the planning process is the thought about as to how do people use places, what kind of co-habitation may they perform, how much space and time do they need and use by any such engagement, what kind of places do they seek for play or rest on their daily routine through the city etc.? How much and how well do then architects, landscape architects and urban designers, actually collaborate with their most numerous and most frequent 'clients', users of urban open public spaces? How much do they actually know about that what spatial elements do stimulate or inhibit certain use or more of them, and what possible co-habitation and events might be expected in different places? This paper critically reflects on a kind and use of knowledge about the users of urban open public spaces in urban design. It shows that designers' perceptions about usage-spatial relationships are inadequate and many times very different from the actual situations. The findings are based on results from the workshops with urban landscape designers and on the base of observation and behavioural mapping. This workshop inquiry was a part of a comprehensive research and was intended as a pilot study rather than a fully-fledged investigation. Designers' views and beliefs about public space design and its potential use resulted from the workshops with urban landscape designers, a sample of 35 participants in all, using two approaches: mapping out likely uses in detailed maps of selected places, and revealing a physical structure of a particular place by knowing its behavioural patterns. Data collected by the workshops is reliable because of asking experts of urban landscape design about place design or its potential use in places that were unfamiliar to them. Although there was a common introduction to each task in the workshop, workshop participants dealt with each task individually. Although a sizable group of workshop participants responded very well, there was still about the same number of designers who seemed to be much less sensitive to these usage-spatial concerns. However, it should be born in mind that the workshop participants were subjects to major time constrains and other pressures such as: an intensive introduction about places, limited time for any drawing tasks and no individual discussions, therefore there is no intention to make undue criticism. Nevertheless, the range of illustrations in the paper shows that designers' perceptions about uses and places are not always in harmony and that, for still to many of them, there is insufficient awareness of this link between places and people's use of them. From this point of view, the paper also reveals a need for effective design-research integration and stresses the importance of empirical knowledge and its incorporation in design.