is this a fact based on previous experiences or opinion?
This is only common sense and not Official Policy.
In practice however, many folks just like find that officially giving up greencards facilitates issuance of B-visas and continued annual "visits" for their real purposes of just visiting family and for vacations and business trips. Officially surrendering a greencard and completing form I-407 abroad and applying for a B visa (rather than being stripped of a greencard through a formal Removal Proceeding initiated by CBP upon entry) is solid evidence of "nonimmigrant" intent and purpose for that trip and future trips. It is always situational to the specifics of the case.
9 FAM 41.31 N15 LAWFUL PERMANENT RESIDENT (LPR) ISSUED NONIMMIGRANT VISITOR VISA FOR EMERGENCY TEMPORARY VISIT TO UNITED STATES
(CT:VISA-1150; 02-10-2009)
A lawful permanent resident (LPR) may, in some cases, need to get a visa more quickly than obtaining a returning resident visa would permit. For example: a permanent resident alien employed by a U.S. corporation is temporarily assigned abroad but has not necessarily remained more than one year and may not use Form I-551, Permanent Resident Card, in order to travel to the United States for an urgent conference and then return abroad. The alien has never relinquished permanent residence, has continued to pay U.S. income taxes, and perhaps even maintains a home in the United States. The alien may be issued a nonimmigrant visa for this purpose and Form I-551 need not be surrendered.
The relinquishment of either of these forms shall not be required as a condition precedent to the issuance of either an immigrant or nonimmigrant visa (NIV) unless the Department of Homeland Security (DHS) has requested such action.
9 FAM 42.22 N1.10 Alien Employed Abroad by U.S. Employer
(CT:VISA-1377; 11-24-2009)
In the absence of contrary evidence, an alien employed outside the United States by a U.S. employer would not likely be considered to have abandoned U.S. residence. Although an alien who lives and works in a foreign country, but merely returns to the United States for brief visits periodically may still be found to have abandoned LPR status.
Annual visits to the United States are no guarantee that LPR status will be preserved.
SB-1 cases see:
http://www.state.gov/documents/organization/87545.pdf
URGENT or EMERGENCY travel needed by an LPR who cannot wait for the SB-1 process may get a B visa and then return abroad for SB-1 processing:
SEE:
http://www.state.gov/documents/organization/87206.pdf