It is not up to AP vendor, it is more up to settings you will put on your access point.
If you take Wi-Fi Certified equipment you should not have a problem.
1. You could disable SSID broadcast so only stations with configured SSID could connect to it.
2. Use WPA instead of WEP.
3. Use MAC filtering.
4. If you are dealing with confidential data use also IPsec.
More about this issue check on:
Security for WLAN